Methods for delivering a prosthetic valve

ABSTRACT

Methods for delivering a prosthetic valve comprise introducing the prosthetic heart valve into a body of a patient. The prosthetic valve is mounted within a delivery sheath of a delivery apparatus in a radially compressed state. The prosthetic valve is advanced through the body to a delivery location. A motor is actuated to cause the delivery sheath to retract to expose the prosthetic valve and the prosthetic valve expands to a radially expanded state at the delivery location. The methods can also include releasing the prosthetic valve from the delivery apparatus and removing the delivery apparatus from the patient.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/181,243, filed Jun. 13, 2016, which is a continuation of U.S. patentapplication Ser. No. 14/182,169, filed Feb. 17, 2014, which is acontinuation of U.S. patent application Ser. No. 12/429,040, filed Apr.23, 2009, now U.S. Pat. No. 8,652,202, which claims the benefit of U.S.Application No. 61/091,293, filed Aug. 22, 2008, all of theseapplications are incorporated herein by reference.

FIELD

The present invention concerns embodiments of a prosthetic heart valveand a delivery apparatus for implanting a prosthetic heart valve.

BACKGROUND

Prosthetic cardiac valves have been used for many years to treat cardiacvalvular disorders. The native heart valves (such as the aortic,pulmonary and mitral valves) serve critical functions in assuring theforward flow of an adequate supply of blood through the cardiovascularsystem. These heart valves can be rendered less effective by congenital,inflammatory or infectious conditions. Such damage to the valves canresult in serious cardiovascular compromise or death. For many years thedefinitive treatment for such disorders was the surgical repair orreplacement of the valve during open heart surgery, but such surgeriesare prone to many complications. More recently a transvascular techniquehas been developed for introducing and implanting a prosthetic heartvalve using a flexible catheter in a manner that is less invasive thanopen heart surgery.

In this technique, a prosthetic valve is mounted in a crimped state onthe end portion of a flexible catheter and advanced through a bloodvessel of the patient until the valve reaches the implantation site. Thevalve at the catheter tip is then expanded to its functional size at thesite of the defective native valve such as by inflating a balloon onwhich the valve is mounted. Alternatively, the valve can have aresilient, self-expanding stent or frame that expands the valve to itsfunctional size when it is advanced from a delivery sheath at the distalend of the catheter.

Balloon-expandable valves typically are preferred for replacingcalcified native valves because the catheter balloon can applysufficient expanding force to anchor the frame of the prosthetic valveto the surrounding calcified tissue. On the other hand, self-expandingvalves typically are preferred for replacing a defective, non-stenotic(non-calcified) native valve. One drawback associated with implanting aself-expanding valve is that as the operator begins to advance the valvefrom the open end of the delivery sheath, the valve tends to “jump” outvery quickly from the end of the sheath; in other words, the outwardbiasing force of the valve's frame tends to cause the valve to beejected very quickly from the distal end of the delivery sheath, makingit difficult to deliver the valve from the sheath in a precise andcontrolled manner and increasing the risk of trauma to the patient.

Another problem associated with implanting a percutaneous prostheticvalve in a non-stenotic native valve is that the prosthetic valve maynot be able to exert sufficient force against the surrounding tissue toresist migration of the prosthetic valve. Typically, the stent of theprosthetic valve must be provided with additional anchoring orattachment devices to assist in anchoring the valve to the surroundingtissue. Moreover, such anchoring devices or portions of the stent thatassist in anchoring the valve typically extend into and become fixed tonon-diseased areas of the vasculature, which can result in complicationsif future intervention is required, for example, if the prosthetic valveneeds to be removed from the patient.

SUMMARY

Certain embodiments of the present disclosure provide a prosthetic heartvalve and a heart valve delivery apparatus for delivery of theprosthetic heart valve to a native valve site via the human vasculature.The delivery apparatus is particularly suited for advancing a prostheticvalve through the aorta (i.e., in a retrograde approach) for replacing adiseased native aortic valve.

In one embodiment of a prosthetic heart valve, the valve comprises aradially expandable and compressible support frame, or stent, and pluralleaflets supported by the stent. The stent desirably comprises aplurality of strut members interconnected to each other to form a meshstructure having an inflow end and an outflow end. The mesh structurecan have an overall curved shape that tapers inwardly from the inflowend to a reduced diameter section, increases in diameter from thereduced diameter section to a distended intermediate section, and thentapers from the intermediate section to toward the outflow end of themesh structure. The valve can be implanted in a native aortic valve suchthat the reduced diameter section resides within the annulus of thenative valve, the inflow end portion extends slightly below the valveannulus and the distended intermediate section extends slightly abovethe valve annulus into the Valsalva's sinuses. The flared inflow endportion and the distended intermediate section are greater in diameterthan the native annulus and therefore assist in retaining the valve inplace against forces tending to dislodge the valve in the upstream anddownstream directions. Due to the geometry of the stent, the valve isparticularly suited for replacing a non-stenotic valve, which typicallydoes not anchor a prosthetic valve as well as a calcified native valve.The stent desirably does not include additional anchoring devices orframe portions to assist in anchoring the valve in place. Consequently,the valve can be implanted without contacting non-diseased areas of thevasculature, which prevents or at least minimizes complications iffuture intervention is required.

The plural leaflets of the valve have respective inflow end portions andoutflow end portions. The inflow end portions of the leaflets can besecured to the inside of the mesh structure at the inflow end portion ofthe mesh structure. The outflow end portions of the leaflets defineangularly spaced commisures that can be secured to the inside of themesh structure at the outflow end of the mesh structure.

A delivery apparatus for delivering a self-expanding prosthetic valvecan be configured to allow controlled and precise deployment of thevalve from a valve sheath so as to minimize or prevent jumping of thevalve from the valve sheath. In one embodiment, the valve is connectedto the distal end of an elongated valve catheter and the sheath extendsfrom a distal end of an outer catheter that extends over the valvecatheter. To deploy the valve from the sheath, the valve catheter isrotated relative to the outer catheter and the sheath to effect slidingmovement of the sheath relative to the valve until the valve is deployedfrom the distal end of the sheath. As the valve is advanced from thesheath, the valve catheter retains the valve against uncontrolledadvancement or jumping of the valve from the sheath that can be causedby the natural resiliency of the valve. In another embodiment, the outershaft can be connected to a screw shaft located in the handle of thedelivery apparatus. The screw shaft can be operatively connected to anactuator knob that is rotated by the user to move the screw shaft andthe outer shaft in the longitudinal directions. Longitudinal movement ofthe outer shaft in the proximal direction is effective to retract thesheath relative to the valve to deploy the valve from the sheath in aprecise and controlled manner.

The delivery apparatus can include a retaining mechanism that forms areleasable connection between the valve and the distal end of thedelivery apparatus. The retaining mechanism retains the valve relativeto the delivery apparatus after the valve is deployed from the sheath toallow the user to adjust the position of the expanded valve relative tothe target implantation site. In one embodiment, the retaining mechanismcan include a first fork having a plurality of prongs formed withopenings that receive respective posts of the valve's stent. A secondfork has a plurality of prongs that extend through respective openingsin the prongs of the first fork to form a releasable connection witheach post of the stent. By virtue of this arrangement, the position ofthe expanded valve can be adjusted within the patient's body bymanipulating the handle of the delivery apparatus. To release the valve,the second fork is retracted to withdraw its prongs from the openings inthe stent, leaving the valve implanted in the body. In anotherembodiment, the retaining mechanism can comprise a plurality of suturesthat extend from the distal end of the delivery apparatus. Each sutureextends through an opening or hook portion of the stent and has a loopat its distal end through which a release wire extends. The release wiresecures each suture to a portion of the stent. To release the valve, therelease wire is retracted from the suture loops, allowing the sutures torelease the valve from the distal end of the delivery apparatus.

In a representative embodiment, a heart-valve delivery apparatus fordelivering a prosthetic heart valve via a patient's vasculature,comprises a catheter comprising a flexible torque shaft adapted toextend through the vasculature, the torque shaft having a distal endportion coupled to the prosthetic valve, and a valve sheath configuredto receive the valve in a radially compressed state when coupled to thedistal end portion of the catheter for delivery to the heart through thepatient's vasculature. The apparatus is configured such that rotation ofthe torque shaft is effective to cause relative longitudinal movementbetween the sheath and the valve to advance the valve from the sheathfor deployment in the heart.

In another representative embodiment, a method is provided forimplanting a prosthetic, self-expanding heart valve in a patient's body.The method comprises mounting the valve in a radially compressed statewithin a sheath of a delivery apparatus, the valve being coupled to anelongated catheter of the delivery apparatus, inserting the deliveryapparatus into the patient's vasculature and advancing the valve towardan implantation site, and rotating the catheter relative to the sheath,which causes relative longitudinally movement between the sheath andcatheter to advance the valve from the sheath and expand.

In another representative embodiment, a heart-valve delivery apparatusfor delivering a prosthetic, stented heart valve via a patient'svasculature comprises at least one elongated catheter having a distalend portion, and a valve-retaining mechanism coupling the valve to thedistal end portion of the catheter. The retaining mechanism comprises afirst fork and a second fork, each fork having a plurality of angularlyspaced prongs, each prong of the first fork cooperating with acorresponding prong of the second fork to form a releasable connectionwith the stent of the valve, the second fork being movable relative tothe first fork to release each connection formed by the prongs and thestent.

In another representative embodiment, a method is provided forimplanting a prosthetic heart valve in a patient's body, the valvecomprising a radially compressible and expandable stent. The methodcomprises connecting the valve in a compressed state to the distal endof a delivery apparatus via a retaining mechanism comprising a firstfork and a second fork, each fork having a plurality of angularly spacedprongs, each prong of the first fork cooperating with a correspondingprong of the second fork to form a releasable connection with the stentof the valve. The method further comprises inserting the deliveryapparatus into the patient's vasculature and advancing the valve to animplantation site in the heart, expanding the valve at a position at oradjacent the implantation site, and moving the second fork relative tothe first fork to release each connection formed by the prongs and thestent, thereby releasing the valve from the delivery apparatus.

In yet another representative embodiment, a prosthetic heart valve forimplantation at an implantation site having an annulus comprises aradially expandable and compressible support frame. The support framecomprises a plurality of strut members interconnected to each other toform a mesh structure comprising an inflow end and an outflow end. Themesh structure comprises a distended intermediate portion having a firstdiameter at a first location, the intermediate portion tapering in adirection toward the inflow end to form an inflow end portion having asecond, smaller diameter at a second location. The valve furthercomprises plural leaflets having respective inflow end portions andoutflow end portions, the inflow end portions of the leaflets beingsecured to the inside of the mesh structure at the inflow end portion ofthe mesh structure, and the outflow end portions of the leafletsdefining angularly spaced commisures that are secured to the inside ofthe mesh structure at the outflow end of the mesh structure.

In another representative embodiment, a delivery apparatus fordelivering a prosthetic heart valve comprises a first elongated shafthaving a proximal end and a distal end adapted to be connected to thevalve, and a second elongated shaft extending over the first shaft andhaving a proximal end and a distal end portion comprising a sheathconfigured to extend over the valve when the valve is in a radiallycompressed state. A handle is coupled to the proximal ends of the firstand second shafts, the handle comprising a rotatable actuator and ascrew operatively connected to the actuator and connected to theproximal end of the second shaft, wherein rotation of the actuatorcauses longitudinal movement of the screw and second shaft relative tothe first shaft to retract the sheath relative to the valve.

In another representative embodiment, a delivery apparatus fordelivering a prosthetic heart valve having a stent comprises at leastone elongated catheter having a distal end portion, and a releasablevalve-retaining mechanism adapted to form a releasable connectionbetween the valve and the distal end portion of the catheter. Thevalve-retaining mechanism comprises a plurality of sutures extendingfrom the distal end portion of the catheter, each suture extendingthrough and engaging a portion of the stent and having a loop at oneend. The valve-retaining mechanism further comprises an elongatedslidable member extending through the loops of each suture so as toconnect the valve to the catheter. The slidable member is retractablerelative to the sutures to release the loops from the slidable member,thereby releasing the connection between the valve and the catheter.

In another representative embodiment, a delivery apparatus fordelivering a prosthetic heart valve, comprises an elongated catheterhaving a distal end portion adapted to be coupled to the prostheticvalve, and a valve sheath. The valve sheath is configured to extend overthe valve in a radially compressed state when coupled to the distal endportion of the catheter, and comprises a folded portion formed from afirst tubular fold layer that extends over the valve and a secondtubular fold layer that extends over the first fold layer. The secondfold layer is moveable longitudinally relative to the catheter and thevalve to unsheathe the valve.

In another representative embodiment, an assembly comprises a prostheticvalve comprising a self-expanding stent, the stent having a plurality ofangularly spaced posts, and a delivery apparatus for delivering thevalve to an implantation site in a patient's body. The deliveryapparatus comprises an elongated shaft having a distal end portion, thedistal end portion having a plurality of recesses formed in an outersurface thereof and sized to receive respective posts of the stent. Thedelivery apparatus also comprises an outer sheath sized to extend overthe valve and retain the valve in a compressed state with the postsdisposed in respective recesses, the sheath and the shaft being moveablelongitudinally relative to each other to unsheathe the valve, therebyallowing it to expand.

In another representative, an introducer sheath comprising an elongatedtubular sleeve having a lumen and adapted to be inserted into apatient's vasculature. The sleeve comprises a metallic layer comprisinga plurality of bands spaced along a length of the metallic layer andcircumferentially extending openings interposed between adjacent bands.The introducer sheath can further comprise a seal housing coupled to aproximal end of the sleeve.

In yet another representative embodiment, an introducer sheath comprisesa housing having an inner bore, cap portion moveable longitudinally onthe housing, an elastomeric seal mounted to the cap portion and havingan opening aligned with the inner bore. The cap portion is moveable froma first position to a second position on the housing to stretch the sealin the radial direction in order to dilate the opening in the seal. Theintroducer sheath can also include

an elongated tubular sleeve extending from the inner bore of thehousing, the sleeve having a lumen and adapted to be inserted into apatient's vasculature.

The foregoing and other features and advantages of the invention willbecome more apparent from the following detailed description, whichproceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a prosthetic valve that can be used toreplace the native aortic valve of the heart.

FIG. 2 is a perspective view of a portion of the valve of FIG. 1illustrating the connection of two leaflets to the support frame of thevalve.

FIG. 3 is side elevation view of the support frame of the valve of FIG.1.

FIG. 4 is a perspective view of the support frame of the valve of FIG.1.

FIG. 5A is a cross-sectional view of the heart showing the prostheticvalve of FIG. 1 implanted within the aortic annulus.

FIG. 5B is an enlarged view of FIG. 5A illustrating the prosthetic valveimplanted within the aortic annulus, shown with the leaflet structure ofthe valve removed for clarity.

FIG. 6 is a perspective view of the leaflet structure of the valve ofFIG. 1 shown prior to being secured to the support frame.

FIG. 7 is a cross-sectional view of the valve of FIG. 1.

FIG. 8 is an exploded view of a delivery apparatus that can be used todeliver and implant a prosthetic valve, such as the prosthetic valveshown in FIG. 1.

FIG. 9 is a side view of the distal end portion of the deliveryapparatus shown with a sheath extending over and covering a valve fordelivery through a patient's vasculature.

FIG. 10 is a side view of the distal end portion of the deliveryapparatus shown with the sheath retracted to allow the valve to expandto its functional size.

FIG. 11 is a cross-section view of the distal end portion of thedelivery apparatus.

FIG. 12 is a cross-sectional view of a portion of the delivery apparatusshowing the inside of the sheath.

FIG. 13 is an exploded, perspective view of the valve and a retainingmechanism that forms a releasable connection between the valve and thedelivery apparatus.

FIG. 14 is a perspective view showing the valve connected to theretaining mechanism.

FIG. 15 is an enlarged, perspective view of a portion of the retainingmechanism illustrating two prongs of the retaining cooperating to form areleasable connection with the support frame of the valve.

FIG. 16 is an enlarged, cross-sectional view of a portion of thedelivery apparatus.

FIG. 17 is a perspective view of the valve and a loading cone that canbe used to radially compress the valve to a compressed stated forloading into the sheath.

FIG. 18 shows the valve being inserted through the cone to compress thevalve.

FIGS. 19 and 20 show the distal end portion of a torque catheter beingconnected to an inner fork of the retaining mechanism.

FIGS. 21 and 22 show a screw member disposed on the torque catheterbeing connected to an outer fork of the retaining mechanism.

FIGS. 23 and 24 show the compressed valve being loaded into the sheathof the delivery apparatus.

FIG. 25 is a side view of the delivery apparatus showing the sheathpartially retracted.

FIGS. 26 and 27 show the inner fork of the retaining mechanism beingretracted relative to the outer fork to release the valve from theretaining mechanism.

FIG. 28 shows the retaining mechanism being retracted into the sheathafter the valve is released and deployed in the body.

FIG. 29A is a cross-sectional view of the distal end portion of anotherembodiment of a delivery apparatus.

FIG. 29B is a cross-sectional view of the distal end portion of anotherembodiment of a delivery apparatus.

FIG. 30 is a side view of the distal end portion of another embodimentof a delivery apparatus.

FIG. 31 is a side view similar to FIG. 30 showing the sheath of thedelivery apparatus in a partially retracted position.

FIG. 32 is a side view similar to FIG. 30 shown with the sheath removedfor purposes of illustration.

FIG. 33 is a side view similar to FIG. 32 showing a portion of thedelivery apparatus in a bent position. This figure illustrates that thedelivery apparatus can exhibit sufficient flexibility along the portioncontaining the screw mechanism.

FIG. 34 is a perspective view of the handle portion of the deliveryapparatus shown in FIG. 30, according to one embodiment.

FIG. 35 is a perspective view illustrating the inside of the handleportion.

FIG. 36 is a side view illustrating the deployment of a valve from thesheath of the delivery apparatus of FIG. 30.

FIG. 37 is a side view illustrating the operation of the retainingmechanism of the delivery apparatus of FIG. 30.

FIGS. 38A-38C illustrate the operation of a valve-retrieval device beingused to retrieve an expanded valve back into a delivery apparatus forremoval from the body.

FIG. 39 is a side view of another embodiment of a delivery apparatus.

FIG. 40 is a perspective view of another embodiment of a deliveryapparatus.

FIG. 41 is an enlarged, cross-sectional view of the handle assembly ofthe delivery apparatus of FIG. 40.

FIG. 42 is an exploded, perspective view of the handle assembly shown inFIG. 41.

FIG. 43 is an enlarged, perspective view of the sheath adjustment knobof the handle assembly shown in FIG. 41.

FIG. 44 is a cross-sectional view of the sheath adjustment knob shown inFIG. 43.

FIG. 45 is an enlarged, front elevation view of the engagement latch ofthe adjustment knob shown in FIG. 43.

FIG. 46 is an enlarged, perspective view of the distal end portion ofthe delivery apparatus shown in FIG. 40.

FIG. 47 is an enlarged, perspective view of the distal end portion ofthe delivery apparatus of FIG. 40 shown with the sheath retracted toillustrate sutures used to secure a prosthetic valve (not shown) to thedelivery apparatus.

FIG. 48 is an enlarged, cross-sectional view of the distal end portionof the delivery apparatus of FIG. 40 illustrating a technique forforming a releasable connection between a prosthetic valve and thedelivery apparatus.

FIG. 49 is an enlarged, perspective view of the distal end portion ofthe delivery apparatus of FIG. 40 shown with the sheath retracted andthe expanded valve secured to the delivery apparatus by the releasableconnection.

FIG. 50 is an enlarged, perspective view of the distal end of thedelivery apparatus similar to FIG. 49 but showing an alternativetechnique for forming a releasable connection between the valve and thedelivery apparatus.

FIG. 51 is an enlarged, perspective view of the distal end of thedelivery apparatus similar to FIG. 49 but showing another technique forforming a releasable connection between the valve and the deliveryapparatus.

FIGS. 52A and 52B are cross-sectional views of the distal end portion ofa delivery apparatus, according to another embodiment.

FIG. 53A is a cross-sectional view of the distal end portion of adelivery apparatus, according to another embodiment.

FIG. 53B is an enlarged view of a portion of FIG. 53A showing theconnection between the valve stent and the distal end of the deliveryapparatus.

FIG. 53C is a perspective view of the delivery apparatus of FIG. 53A.

FIGS. 53D and 53E illustrate the valve being deployed from the deliveryapparatus shown in FIG. 53A.

FIG. 54A is a perspective view of a delivery apparatus for a prostheticvalve shown with the sheath of the delivery apparatus in a retractedposition for deploying the valve, according to another embodiment.

FIG. 54B is a perspective view of the delivery apparatus of FIG. 54Ashown with the sheath in a distal position for covering the valve duringvalve delivery.

FIG. 54C is an enlarged, perspective view of an end piece of thedelivery apparatus of FIG. 54A and three posts of a valve stent that arereceived within respective recesses in the end piece.

FIG. 54D is a cross-sectional view of the end piece shown in FIG. 54C.

FIGS. 55A and 55B are cross-sectional views of an embodiment of a loaderdevice that can be used with an introducer sheath for introducing adelivery apparatus into the body.

FIGS. 56A and 56B are cross-sectional views of another embodiment of aloader device.

FIGS. 57A and 57B are cross-sectional views of an introducer sheath andloader assembly, according to one embodiment.

FIG. 58A is a perspective view of an introducer sheath, according toanother embodiment.

FIG. 58B is an enlarged, perspective view of the sleeve of theintroducer sheath of FIG. 58A.

FIG. 59 is an enlarged, perspective view of another embodiment of asleeve that can be used with the introducer sheath of FIG. 58A.

FIG. 60 is an end view of a sleeve that can be used with the introducersheath of FIG. 58A.

DETAILED DESCRIPTION

Referring first to FIG. 1, there is shown a prosthetic aortic heartvalve 10, according to one embodiment. The valve 10 includes anexpandable frame member, or stent, 12 that supports a flexible leafletsection 14. The valve 10 is radially compressible to a compressed statefor delivery through the body to a deployment site and expandable to itsfunctional size shown in FIG. 1 at the deployment site. In certainembodiments, the valve 10 is self-expanding; that is, the valve canradially expand to its functional size when advanced from the distal endof a delivery sheath. Apparatuses particularly suited for percutaneousdelivery and implantation of a self-expanding valve are described indetail below. In other embodiments, the valve can be aballoon-expandable valve that can be adapted to be mounted in acompressed state on the balloon of a delivery catheter. The valve can beexpanded to its functional size at a deployment site by inflating theballoon, as known in the art.

The illustrated valve 10 is adapted to be deployed in the native aorticannulus, although it also can be used to replace the other native valvesof the heart. Moreover, the valve 10 can be adapted to replace othervalves within the body, such a venous valve.

FIGS. 3 and 4 show the stent 12 without the leaflet section 14 forpurposes of illustration. As shown, the stent 12 can be formed from aplurality of longitudinally extending, generally sinusoidal shaped framemembers, or struts, 16. The struts 16 are formed with alternating bendsand are welded or otherwise secured to each other at nodes 18 formedfrom the vertices of adjacent bends so as to form a mesh structure. Thestruts 16 can be made of a suitable shape memory material, such as thenickel titanium alloy known as Nitinol, that allows the valve to becompressed to a reduced diameter for delivery in a delivery apparatus(such as described below) and then causes the valve to expand to itsfunctional size inside the patient's body when deployed from thedelivery apparatus. If the valve is a balloon-expandable valve that isadapted to be crimped onto an inflatable balloon of a delivery apparatusand expanded to its functional size by inflation of the balloon, thestent 12 can be made of a suitable ductile material, such as stainlesssteel.

The stent 12 has an inflow end 26 and an outflow end 27. The meshstructure formed by struts 16 comprises a generally cylindrical “upper”or outflow end portion 20, an outwardly bowed or distended intermediatesection 22, and an inwardly bowed “lower” or inflow end portion 24. Theintermediate section 22 desirably is sized and shaped to extend into theValsalva sinuses in the root of the aorta to assist in anchoring thevalve in place once implanted. As shown, the mesh structure desirablyhas a curved shape along its entire length that gradually increases indiameter from the outflow end portion 20 to the intermediate section 22,then gradually decreases in diameter from the intermediate section 22 toa location on the inflow end portion 24, and then gradually increases indiameter to form a flared portion terminating at the inflow end 26.

When the valve is in its expanded state, the intermediate section 22 hasa diameter D₁, the inflow end portion 24 has a minimum diameter D₂, theinflow end 26 has a diameter D₃, and the outflow end portion 20 has adiameter D₄, where D₂ is less than D₁ and D₃ and D₄ is less than D₂. Inaddition, D₁ and D₃ desirably are greater than the diameter than thenative annulus in which the valve is to be implanted. In this manner,the overall shape of the stent 12 assists in retaining the valve at theimplantation site. More specifically, and referring to FIGS. 5A and 5B,the valve 10 can be implanted within a native valve (the aortic valve inthe illustrated example) such that the lower section 24 is positionedwithin the aortic annulus 28, the intermediate section 24 extends abovethe aortic annulus into the Valsalva's sinuses 56, and the lower flaredend 26 extends below the aortic annulus. The valve 10 is retained withinthe native valve by the radial outward force of the lower section 24against the surrounding tissue of the aortic annulus 28 as well as thegeometry of the stent. Specifically, the intermediate section 24 and theflared lower end 26 extend radially outwardly beyond the aortic annulus28 to better resist against axial dislodgement of the valve in theupstream and downstream directions (toward and away from the aorta).Depending on the condition of the native leaflets 58, the valvetypically is deployed within the native annulus 28 with the nativeleaflets 58 folded upwardly and compressed between the outer surface ofthe stent 12 and the walls of the Valsalva sinuses, as depicted in FIG.5B. In some cases, it may be desirable to excise the leaflets 58 priorto implanting the valve 10.

Known prosthetic valves having a self-expanding frame typically haveadditional anchoring devices or frame portions that extend into andbecome fixed to non-diseased areas of the vasculature. Because the shapeof the stent 12 assists in retaining the valve, additional anchoringdevices are not required and the overall length L of the stent can beminimized to prevent the stent upper portion 20 from extending into thenon-diseased area of the aorta, or to at least minimize the extent towhich the upper portion 20 extends into the non-diseased area of theaorta. Avoiding the non-diseased area of the patient's vasculature helpsavoid complications if future intervention is required. For example, theprosthetic valve can be more easily removed from the patient because thestent is primarily anchored to the diseased part of the valve.

In particular embodiments, for a valve intended for use in a 22-mm to24-mm annulus, the diameter D1 is about 28 mm to about 32 mm, with 30 mmbeing a specific example; the diameter D2 is about 24 mm to about 28 mm,with 26 mm being a specific example; the diameter D3 is about 28 mm toabout 32 mm, with 30 mm being a specific example; and the diameter D4 isabout 24 mm to about 28 mm, with 26 mm being a specific example. Thelength L in particular embodiments is about 20 mm to about 24 mm, with22 mm being a specific example.

Referring to FIG. 1, the stent 12 can have a plurality of angularlyspaced retaining arms, or projections, in the form of posts 30 (three inthe illustrated embodiment) that extend from the stent upper portion 20.Each retaining arm 30 has a respective aperture 32 that is sized toreceive prongs of a valve-retaining mechanism that can be used to form areleasable connection between the valve and a delivery apparatus(described below). In alternative embodiments, the retaining arms 30need not be provided if a valve-retaining mechanism is not used.

As best shown in FIGS. 6 and 7, the leaflet assembly 14 in theillustrated embodiment comprises three leaflets 34 a, 34 b, 34 c made ofa flexible material. Each leaflet has an inflow end portion 60 and anoutflow end portion 62. The leaflets can comprise any suitablebiological material (e.g., pericardial tissue, such as bovine or equinepericardium), bio-compatible synthetic materials, or other suchmaterials, such as those described in U.S. Pat. No. 6,730,118, which isincorporated herein by reference. The leaflet assembly 14 can include anannular reinforcing skirt 42 that is secured to the outer surfaces ofthe inflow end portions of the leaflets 34 a, 34 b, 34 c at a sutureline 44 adjacent the inflow end of the valve. The inflow end portion ofthe leaflet assembly 14 can be secured to the stent 12 by suturing theskirt 42 to struts 16 of the lower section 24 of the stent (best shownin FIG. 1). As shown in FIG. 7, the leaflet assembly 14 can furtherinclude an inner reinforcing strip 46 that is secured to the innersurfaces of the inflow end portions 60 of the leaflets.

Referring to FIGS. 1 and 2, the outflow end portion of the leafletassembly 14 can be secured to the upper portion of the stent 12 at threeangularly spaced commissure attachments of the leaflets 34 a, 34 b, 34c. As best shown in FIG. 2, each commissure attachment can be formed bywrapping a reinforcing section 36 around adjacent upper edge portions 38at the commissure of two leaflets and securing the reinforcing section36 to the edge portions 38 with sutures 48. The sandwiched layers of thereinforcing material and leaflets can then be secured to the struts 16of the stent 12 with sutures 50 adjacent the outflow end of the stent.The leaflets therefore desirably extend the entire length orsubstantially the entire length of the stent from the inflow end 26 tothe outflow end 27. The reinforcing sections 36 reinforces theattachment of the leaflets to the stent so as to minimize stressconcentrations at the suture lines and avoid “needle holes” on theportions of the leaflets that flex during use. The reinforcing sections36, the skirt 42, and the inner reinforcing strip 46 desirably are madeof a bio-compatible synthetic material, such as polytetrafluoroethylene(PTFE), or a woven fabric material, such as woven polyester (e.g.,polyethylene terephthalate) (PET)).

FIG. 7 shows the operation of the valve 10. During diastole, theleaflets 34 a, 34 b, 34 c collapse to effectively close the valve. Asshown, the curved shape of the intermediate section 22 of the stent 12defines a space between the intermediate section and the leaflets thatmimics the Valsalva sinuses. Thus, when the leaflets close, backflowentering the “sinuses” creates a turbulent flow of blood along the uppersurfaces of the leaflets, as indicated by arrows 52. This turbulenceassists in washing the leaflets and the skirt 42 to minimize clotformation.

The valve 10 can be implanted in a retrograde approach where the valve,mounted in a crimped state at the distal end of a delivery apparatus, isintroduced into the body via the femoral artery and advanced through theaortic arch to the heart, as further described in U.S. PatentPublication No. 2008/0065011, which is incorporated herein by reference.

FIG. 8 shows a delivery apparatus 100, according to one embodiment, thatcan be used to deliver a self-expanding valve, such as valve 10described above, through a patient's vasculature. The delivery apparatus100 comprises a first, outermost or main catheter 102 having anelongated shaft 104, the distal end of which is coupled to a deliverysheath 106 (also referred to as a delivery cylinder). The proximal endof the main catheter 102 is connected to a handle of the deliveryapparatus (not shown). During delivery of a valve, the handle can beused by a surgeon to advance and retract the delivery apparatus throughthe patient's vasculature. Although not required, the main catheter 102can comprise a guide catheter that is configured to allow a surgeon toguide or control the amount the bending or flexing of a distal portionof the shaft 104 as it is advanced through the patient's vasculature,such as disclosed in U.S. Patent Publication No. 2008/0065011.

The delivery apparatus 100 also includes a second catheter 108 (alsoreferred to herein as a valve catheter) having an elongated shaft 110(also referred to herein as a torque shaft), a cylindrical screw 112disposed on the shaft 110, and a valve-retaining mechanism 114 connectedto a distal end portion 116 of the shaft 110. The shaft 110 of the valvecatheter 108 extends through the delivery sheath 106 and the shaft 104of the main catheter 102. The delivery apparatus 100 can also include athird, nose catheter 118 having an elongated shaft 120 and a nose piece122 secured to the distal end portion of the shaft 120. The nose piece122 can have a tapered outer surface as shown for atraumatic trackingthrough the patient's vasculature. The shaft 120 of the nose catheterextends through the valve 10, the retaining mechanism 114, and the shaft110 of the valve catheter 108. The torque shaft 110 of valve catheter108 can be configured to be moveable axially and rotatable relative tothe shaft 104 of the main catheter and the shaft 120 of the nosecatheter. The delivery apparatus 100 can also be provided with a loadingcone 124 that can be used to load the valve 10 in a compressed stateinside the delivery sheath 106, as further described below.

The distal end portion 116 of the valve catheter shaft 110 can includean end piece 156 on which the screw 112 is mounted. The end piece 156has a non-circular cross-sectional profile extending at least partiallyalong the length of the end piece that mates with a similarly shapedinner surface of the screw 112 (as best shown in FIG. 11). For example,in the illustrated embodiment, a portion of the end piece 156 has asquare cross-sectional profile that mates with a square shaped innersurface of the screw 112. In this manner, rotation of the shaft 110causes corresponding rotation of the screw 112.

The valve catheter 108 desirably is configured to be rotatable relativeto the delivery sheath 106 to effect incremental and controlledadvancement of the valve 10 from the delivery sheath. To such ends, andaccording to one embodiment, the delivery sheath 106 (as best shown inFIGS. 9-12) can include first and second elongated cam slots 126 andinternal threads 128 adapted to engage external threads 132 of screw112. The distal end portion of the main catheter shaft 104 extends intothe delivery sheath 106 and can be formed with first and secondprojections 130 that extend radially outwardly into the cam slots 126 ofthe delivery sheath.

As best shown in FIG. 11, the distal end portion of shaft 110 extendsover and is secured to a proximal end portion of the end piece 156, suchas with an adhesive. The screw 112 is disposed on the end piece 56within the delivery sheath 106. The distal end of the screw 112 and theend piece 56 are coupled to the valve 10 via the retaining member 114such that rotation of the valve catheter shaft 110 is effective to causecorresponding rotation of the end piece 56, the screw 112 and the valve10. Rotation of the shaft 110 and the screw 112 relative to the sheath106 is effective to move the shaft 110 and the valve 10 longitudinallyin either the proximal or distal directions (as indicated by arrows 134a and 134 b, respectively) relative to the sheath 106. During valvedeployment, movement of the shaft 110 in the proximal direction causesthe valve 10 to advance from the open distal end 136 of the sheath, asfurther described below.

As best shown in FIGS. 13 and 14, the valve-retaining mechanism 114includes an inner fork 138 an outer fork 140. The inner fork 138includes a plurality of angularly-spaced prongs 142 (three in theillustrated embodiment) corresponding to the retaining arms 30 of thestent 12, which prongs extend from a head portion 144 at the proximalend of the inner fork. The outer fork 140 similarly includes a pluralityof angularly-spaced prongs 146 (three in the illustrated embodiment)corresponding to the retaining arms 30 of the stent 12, which prongsextend from a head portion 148 at the proximal end of the outer fork.

Each prong of the outer fork cooperates with a corresponding prong ofthe inner fork to form a releasable connection with a retaining arm 30of the stent. In the illustrated embodiment, for example, the distal endportion of each prong 146 is formed with an opening 150. When assembled(as best shown in FIG. 15), each retaining arm 30 of the stent isinserted through an opening 150 of a prong 146 of the outer fork and aprong 142 of the inner fork is inserted through the opening 32 of theretaining arm 30 so as to retain the retaining arm 30 from backing outof the opening 150. As can be seen, retracting the prongs 142 proximally(in the direction of arrow 152) to remove the prongs from the openings32 is effective to release the valve 10 from the retaining mechanism. Inthis manner, the retaining mechanism 114 forms a releasable connectionwith the valve that is secure enough to retain the valve relative to thevalve catheter 108 to allow the user to fine tune or adjust the positionof the valve after it is deployed from the delivery sheath. When thevalve is positioned at the desired implantation site, the connectionbetween the valve and the retaining mechanism can be released byretracting the inner fork 138 relative to the outer fork 140, as furtherdescribed below.

The head portion 144 of the inner fork can be connected to the valvecatheter shaft 110 while the head portion 148 can be connected to thescrew 112. As shown in FIG. 13, for example, the head portion 144 of theinner fork can be formed with a plurality of angularly spaced, inwardlybiased retaining flanges 154. The end piece 156 of the valve cathetershaft 110 can be formed with a cylindrical shaft 158 having an annulargroove 160. The shaft 158 has an outer diameter that is slightly greaterthan the diameter defined by the inner free ends of the flanges 154.Thus, the inner fork 138 can be secured to the end piece 156 byinserting the shaft 158 into the head portion 144 until the flanges 154flex inwardly into the groove 160, thereby forming a snap-fit connectionbetween the head portion 144 and the shaft 158. As can be seen in FIG.16, when the head portion 144 is inserted onto the shaft 158, an annularshoulder 162 within the groove 160 is positioned opposite the free endsof flanges 154 and another annular shoulder 164 of end piece 156 ispositioned opposite the proximal end of the head portion 144 to preventthe end piece 156 from moving longitudinally in the distal and proximaldirections relative to the inner fork.

The head portion 148 of the outer fork can be secured to the distal endof the screw 112 in a similar manner. As best shown in FIG. 16, the headportion 148 can be formed with a plurality of angularly spaced, inwardlybiased retaining flanges 155. The distal end portion of the screw 112can be formed with a cylindrical shaft 166 having an annular groove 168.The shaft 166 has an outer diameter that is slightly greater than thediameter defined by the free ends of the flanges 155. Thus, the outerfork 140 can be secured to the screw 112 by inserting the shaft 166 intothe head portion 148 until the flanges flex inwardly into the groove168, thereby forming a snap-fit connection between the head portion 148and the shaft 166. As can be seen in FIG. 16, when the head portion 148is inserted onto the shaft 166, an annular shoulder 170 within thegroove 168 is positioned opposite the free ends of flanges 156 andanother annular shoulder 172 of the screw 112 is positioned opposite theproximal end of the head portion to prevent the screw from movinglongitudinally in the distal and proximal directions relative to theouter fork.

The valve 10 can be compressed and loaded into the delivery sheath 106using the loading cone 124 in the following manner. First, as shown inFIG. 17, the valve 10 can be secured to the retaining mechanism 114 asdescribed above. The loading cone 124 includes a first opening 176 atone end, a second, smaller opening 178 at the opposite end, and atapered inner surface 180 that tapers from a first diameter at the firstopening to a second, smaller diameter proximate the second opening 178.As shown in FIG. 18, the retaining mechanism 114 and the valve 10 can bepushed through the loading cone 124 in the direction of arrow 174 toradially compress the retaining member and the valve until the retainingmember 114 extends outside the loading cone. To facilitate compressionof the valve, the latter step can be performed while immersing the valveand the retaining mechanism in a bath of cold water.

Referring to FIGS. 19 and 20, while the valve is retained in itscompressed state by the loading cone 124, the end piece 156 is securedto the inner fork by inserting the shaft 158 into the head portion 144of the inner fork in the direction of arrow 182 as described above.Referring to FIGS. 21 and 22, the screw 112 can then be slid over theend piece 156 in the direction of arrow 184 and secured to the outerfork 140 by inserting the shaft 166 into the head portion 148 of theouter fork as described above. Subsequently, referring to FIGS. 23 and24, the delivery sheath 106 is placed over the screw 112 by bringing theproximal end of the screw in contact with the distal end of the sheath106 and then rotating the valve catheter shaft 110, which causes thesheath to advance over the screw. Continued rotation of the shaft 110causes the sheath 106 to advance over the retaining member 114 and thevalve 10 and then push away the loading cone to allow the sheath toadvance over the valve as it exits the loading cone. The shaft 110 isrotated until the valve is completely inside the sheath, as depicted inFIGS. 9 and 11.

When nose cone 122 is used, the nose cone desirably has an outerdiameter less than the opening 178 of the loading cone so that the nosecone can slide through the loading cone along with the valve 10. Inalternative embodiments, a conventional crimping mechanism can be usedto radially compress the valve 10.

Once the valve 10 is loaded in the delivery sheath 106, the deliveryapparatus 100 can be inserted into the patient's body for delivery ofthe valve. In one approach, the valve can be delivered in a retrogradeprocedure where delivery apparatus is inserted into a femoral artery andadvanced through the patient's vasculature to the heart. Prior toinsertion of the delivery apparatus, an introducer sheath can beinserted into the femoral artery followed by a guide wire, which isadvanced through the patient's vasculature through the aorta and intothe left ventricle. The delivery apparatus 100 can then be insertedthrough the introducer sheath and advanced over the guide wire until thedistal end portion of the delivery apparatus containing the valve 10 isadvanced to a location adjacent to or within the native aortic valve.

Thereafter, the valve 10 can be deployed from the delivery apparatus 100by rotating the valve catheter 108 relative to the guide catheter 102.As noted above, the valve catheter can have a rotatable handle portion(not shown) connected to the proximal end of the valve catheter shaft110 that allows the surgeon to effect rotation of the valve catheter 108relative to the main catheter 102. Rotation of the valve catheter 108causes corresponding rotation of the valve catheter shaft 110, the endpiece 156, and the screw 112 relative to the main catheter shaft 104 andthe sheath, which in turn causes these components to advance distallyrelative to the delivery sheath 106 to advance the valve 10 from theopen end of the sheath. Rotation of the valve catheter 108 causes thevalve to move relative to sheath in a precise and controlled manner asthe valve advances from the open distal end of the delivery sheath andbegins to expand. Hence, unlike known delivery apparatus, as the valvebegins to advance from the delivery sheath and expand, the valve is heldagainst uncontrolled movement from the sheath caused by the expansionforce of the valve against the distal end of the sheath. In addition,after the valve is partially advanced from the sheath, it may bedesirable to retract the valve back into the sheath, for example, toreposition the valve or to withdraw the valve entirely from the body.The partially deployed valve can be retracted back into the sheath byreversing the rotation of the valve catheter, which causes the cathetershaft 110 to retract and pull the valve back into the sheath.

In known delivery devices, the surgeon must apply push-pull forces tothe shaft and/or the sheath to unsheathe the valve. It is thereforedifficult to transmit forces to the distal end of the device withoutdistorting the shaft (e.g., compressing or stretching the shaftaxially), which in turn causes uncontrolled movement of the valve duringthe unsheathing process. To mitigate this effect, the shaft and/orsheath can be made more rigid, which is undesirable because the devicebecomes harder to steer through the vasculature. In contrast, the mannerof unsheathing the valve described above eliminates the application ofpush-pull forces on the shaft, as required in known devices, so thatrelatively high and accurate forces can be applied to the distal end ofthe shaft without compromising the flexibility of the device. In certainembodiments, as much as 20 lbs. of force can be transmitted to the endof the torque shaft without adversely affecting the unsheathing process.In contrast, prior art devices utilizing push-pull mechanisms typicallycannot exceed about 5 lbs. of force during the unsheathing process.

After the valve 10 is advanced from the delivery sheath and expands toits functional size (as shown in FIG. 10), the valve remains connectedto the delivery apparatus via the retaining mechanism 114. Consequently,after the valve is advanced from the delivery sheath, the surgeon canreposition the valve relative to the desired implantation position inthe native valve such as by moving the delivery apparatus in theproximal and distal directions or side to side, or rotating the deliveryapparatus, which causes corresponding movement of the valve. Theretaining mechanism 114 desirably provides a connection between thevalve and the delivery apparatus that is secure and rigid enough toretain the position of the valve relative to the delivery apparatusagainst the flow of the blood as the position of the valve is adjustedrelative to the desired implantation position in the native valve. Oncethe surgeon positions the valve at the desired implantation position inthe native valve, the connection between the valve and the deliveryapparatus can be released by retracting the valve catheter shaft 110 inthe proximal direction relative to the guide catheter, which iseffective to retract the inner fork 138 to withdraw its prongs 142 fromthe openings 32 in the retaining arms 30 of the valve (FIGS. 26 and 27).Retraction of the delivery apparatus retracts the outer fork 140 tocompletely disconnect the valve from the retaining mechanism 114 (FIG.28). Thereafter, the delivery apparatus can be withdrawn from the body,leaving the valve implanted within the native valve (such as shown inFIGS. 5A and 5B)

In an alternative embodiment, the delivery apparatus can be adapted todeliver a balloon-expandable prosthetic valve. As described above, theretaining mechanism 114 can be used to secure the valve to the end ofthe delivery apparatus. Since the stent of the valve is notself-expanding, the sheath 106 can be optional. The retaining mechanism114 enhances the pushability of the delivery apparatus and valveassembly through the introducer sheath.

FIG. 29A shows the distal end portion of a delivery apparatus 200,according to another embodiment. The delivery apparatus 200 has asimilar construction to and has many of the same components as thedelivery apparatus 100 (some of the common components are removed fromFIG. 29A for clarity). The delivery apparatus 200 comprises an elongatedvalve catheter 202. The valve catheter 202 comprises an elongated,flexible torque shaft 204, an end piece 206 secured to the distal end ofthe shaft 204, and an outer shaft 220 extending over the torque shaft204.

A delivery sheath 208 is secured to the distal end of the outer shaft220. The delivery sheath 208 is disposed over a distal end portion ofthe shaft 204, the end piece 206, a valve-retaining mechanism 114, and avalve 10, which is retained in a compressed state inside the sheath.Only the outer fork 140 of the retaining mechanism 114 is shown in FIG.29A. The head portion 148 of the outer fork 140 can be secured to theend piece 206, such as by forming a snap-fit connection with a steppedshaft portion 210 of the end piece such as described above. The innerfork 138 (not shown in FIG. 29A) can be connected at its head portion144 to the distal end of an inner shaft (not shown in FIG. 29A) thatextends through the valve-catheter shaft. The inner shaft can be theshaft 120 of an elongated nose catheter 118 (FIG. 8). The prongs 142 ofthe inner fork 138 extend through the openings 32 in the stent 12 tosecure the valve 10 to the delivery apparatus, as described in detailabove. Because the inner fork 138 is secured to an inner shaft thatextends through shaft 204, the inner fork 138 can be retracted relativeto the outer fork 140 to withdraw the prongs of the inner fork from theopenings in the stent (and thereby releasing the valve 10) by retractingthe inner shaft in the proximal direction relative to the shaft 204.

The shaft 204 in the illustrated configuration comprises a first layer212 comprising a flexible, slotted tube and second layer 214 comprisinga wire coil that is helically wound around the first layer 212. Thefirst layer 212 can be made of a metal (e.g., stainless steel), apolymeric material, or another suitable material. The wire coil 214 canbe, for example, a stainless steel wire, although other materials can beused. The wire coil 214 extends along at least a distal end portion ofthe shaft 204 and engages internal threads 216 of the sheath 208. Inthis manner, the wire coil 214 serves as external threads of the shaft204. When rotating the torque shaft 204 relative to the outer shaft 220,the sheath 208 is retained against rotating with the shaft 204 by theouter shaft 220 so that rotation of the shaft 204 causes the shaft 204to advance distally relative to the sheath 208 to deploy the valve 10.

In use, the delivery apparatus 200 is inserted into the patient'svasculature and advanced to the implantation site in the heart. Thetorque shaft 204 is then rotated relative to the outer shaft 220 tocause the shaft to advance distally (as indicated by arrow 218) untilthe valve 10 is unsheathed and expands to its functional size. At thispoint, the valve 10 remains connected to the delivery apparatus by theretaining mechanism 114 so that the user can fine-tune the position ofthe expanded valve at the implantation site. Once the valve is in thedesired orientation, the connection formed by the retaining mechanism114 can be released by retracting the inner shaft, as described above.Thereafter, the retaining mechanism can be retracted back into thesheath and the entire delivery apparatus can be removed from the body.

FIG. 29B shows the distal end portion of a delivery apparatus 250,according to another embodiment. The delivery apparatus 250 has asimilar construction to and has many of the same components as thedelivery apparatus 100 (some of the common components are removed fromFIG. 29B for clarity). The delivery apparatus 250 comprises an elongatedvalve catheter 252 comprising an elongated, flexible torque shaft 254that extends into a delivery sheath 256. The shaft 254 can comprise, forexample, a coiled shaft as shown or a cable (e.g., a stainless steelcable). A first screw member 258 is disposed on and secured to a distalend portion of the shaft 254 within the sheath and a second screw member260 is disposed on the first screw member within the sheath. The firstscrew member 258 has external threads that engage internal threads ofthe second screw member 260. The second screw member 260 also hasexternal threads that engage internal threads of the sheath 256.

The delivery apparatus can further include an outer shaft 264 thatextends over the shaft 254 and has a distal end portion that is securedto the proximal end of the sheath 256. The torque shaft 254 can berotated relative to the outer shaft 264 and the sheath 256 to cause thetorque shaft to advance longitudinally relative to the sheath fordeploying the valve from the sheath. A ring member 266 is mounted on theouter surface of the torque shaft 254 and moves longitudinally with thetorque shaft relative to the outer shaft 264 upon rotation of the torqueshaft. The ring member 266 is positioned to contact and cause the secondscrew member 260 to advance within the sheath 256 after the torque shaft254 is advanced distally a predetermined distance, as further describedbelow.

As further shown in FIG. 29B, the outer fork 140 of a valve-retainingmechanism 114 can be secured at its head portion 148 to a stepped shaftportion 262 of the first screw member 258, which in turn is secured tothe torque shaft 254. The inner fork 138 (not shown in FIG. 29B) can beconnected at its head portion to the distal end of an inner shaft (notshown) that extends through the torque shaft 254. The prongs of theinner fork extend from the distal end of the shaft 254 and cooperatewith the prongs of the outer fork to form releasable connections withthe posts 30 of the stent, as described above. The inner fork can beretracted relative to the outer fork to release the connections to theposts 30 by retracting the inner shaft relative to the torque shaft 254.

In use, the delivery apparatus 250 is inserted into the patient'svasculature and advanced to the implantation site in the heart. To begindeployment of the valve, the torque shaft 254 is rotated relative to theouter shaft 264, which causes the first screw member 258 to rotate andadvance distally (in the direction of arrow 268) relative to the secondscrew member 260 and the sheath 258 to partially advance the valve 10from the distal end of the sheath. After the torque shaft 254 isadvanced a predetermined distance, the ring member 266 contacts thesecond screw member 260 so that further rotation of the torque shaft 254is effective to cause the first screw member and the second screw memberto advance distally relative to the sheath to completely advance thevalve 10 from the sheath. Once the valve is in the desired orientation,the connection formed by the retaining mechanism 114 can be released byretracting the inner shaft, as described above. Thereafter, theretaining mechanism can be retracted back into the sheath and the entiredelivery apparatus can be removed from the body.

FIGS. 30-37 illustrate a delivery apparatus 300, according to anotherembodiment. FIGS. 30-33 show the distal end portion of the deliveryapparatus 300. FIGS. 34-35 show the proximal end portion of the deliveryapparatus 300. FIGS. 36-37 show the deployment of a valve 10 from thedelivery apparatus 300 (the leaflets of the valve are removed forclarify in the figures).

The delivery apparatus 300 comprises a first, outer catheter 302 havingan elongated shaft 304 extending between a valve retaining mechanism 306at the distal end of the apparatus (FIGS. 32 and 33) and a handleportion 308 at the proximal end of the apparatus (FIGS. 34 and 35). Thedistal end of the main catheter shaft 304 is coupled to thevalve-retaining mechanism 306, which in turn is secured to the valve 10.The outer catheter 302 can be a guide catheter that is configured topermit selective bending or flexing of a portion of the shaft 304 tofacilitate advancement of the delivery apparatus through the patient'svasculature.

The delivery apparatus also includes a second, torque catheter 310having an elongated torque shaft 312 that extends through the maincatheter shaft 304. The distal end of the torque shaft 304 is connectedto a flexible screw mechanism 314 comprising a flexible shaft 316extending through the retaining mechanism 306 and one or more screwmembers 318 spaced along the length of the shaft 316 (FIGS. 32 and 33).As shown in FIG. 33, the shaft 316 of the screw mechanism 314 exhibitssufficient flexibility to permit bending or flexing to assist intracking the delivery apparatus through the patient's vasculature. Themain catheter shaft 304 can be formed with internal threads that engagethe external threads of the screw members 318. For example, a distal endportion of the main shaft 304 (e.g., an 11-mm segment at the distal endof the shaft 304) can be formed with internal threads. The proximal endportion of the torque shaft 312 extends into the handle portion 308where it is coupled to a control knob 320 to permit rotation of thetorque shaft relative to the main catheter shaft 304 (FIGS. 34 and 35),as further described below.

In operation, each screw member 318 passes through and engages theinternally threaded portion of the main shaft 304. The screw members 318desirably are spaced from each other such that a screw member 318 canengage one end of the internally threaded portion of the main shaft 304before an adjacent screw member 318 disengages from the other end of theinternally threaded portion of the main shaft as the screw members passthrough the internally threaded portion so as to prevent or at leastminimize application of axially directed forces on the torque shaft. Inthis manner, relatively high unsheathing forces can be applied to thesheath without compromising the overall flexibility of the deliveryapparatus.

The delivery apparatus can also include a third, nose catheter 324having an elongated shaft 326 that is connected at its distal end to anose piece 328. The nose catheter shaft 326 extends through the torqueshaft 312 and has a proximal end portion that extends outwardly from theproximal end of the handle portion 308 (FIGS. 34 and 35). The maincatheter shaft 304, the torque shaft 312, and the nose catheter shaft326 desirably are configured to be moveable axially relative to eachother.

As shown in FIGS. 30 and 31, the delivery apparatus can further includea movable sheath 322 that extends over the compressed valve 10. Thesheath 322 is connected to screw mechanism 314 so that longitudinalmovement of the torque shaft 312 and the screw mechanism 314 causescorresponding longitudinal movement of the sheath 322. For example, thesheath can have inwardly extending prongs 358 (FIG. 31) extending intorespective apertures 360 of fingers 362 (FIG. 32), which in turn areconnected to the distal end of the flexible shaft 316. Fingers 362desirably are connected to the shaft 316 by a swivel joint that pushesor pulls fingers 362 when the shaft 316 moves distally or proximally,respective, yet allows the shaft 316 to rotate relative to the fingers362. Consequently, rotation of the torque shaft 312 and the screwmechanism 314 relative to the main shaft 304 is effective to cause thesheath 322 to move in the proximal and distal directions (as indicatedby double-headed arrow 330 in FIG. 30) relative to the valve to permitcontrolled deployment of the valve from the sheath, as further describedbelow.

Referring to FIGS. 32 and 33, the valve-retaining mechanism 306comprises an outer fork 330 and an inner fork 332. A portion of thefinger 362 is cut away in FIG. 33 to show the inner fork 332. The outerfork 330 comprises a head portion 334 and a plurality of elongated,flexible prongs 336 (three in the illustrated embodiment) extending fromthe head portion 334. The head portion 334 can be formed with resilientretaining flanges 338 to permit the outer fork to form a snap-fitconnection with a stepped shaft portion of the main catheter shaft 304,as described above. The inner fork 332 has a head portion 340 that isfixedly secured to the nose catheter shaft 326 and a plurality ofelongated prongs 342 extending from the head portion 340. The distal endportions of the prongs 336 of the outer fork can be formed withapertures 344 sized to receive respective retaining arms 30 of the valve10. The distal ends of the prongs 342 of the inner fork 332 extendthrough the apertures 32 in the retaining arms 30 to form a releasableconnection for securing the valve 10, similar to valve-retainingmechanism 114 described above and shown in FIGS. 14-16. After the valveis deployed form the sheath 322, the connection between the valve andthe retaining mechanism 306 can be released by retracting the nosecatheter shaft 326 relative to the main catheter shaft 304 to withdrawnthe prongs 342 from the apertures 32 in the retaining arms 30. The outerprongs 336 and the shaft 316 of the screw mechanism 314 exhibitsufficient flexibility to allow that portion of the delivery apparatusto bend or flex as the delivery apparatus is advanced through thepatient's vasculature to the implantation site, yet are rigid enough topermit repositioning of the valve after it is deployed from the sheath322. The outer fork 330, including prongs 336, can be made from any ofvarious suitable materials, such as metals (e.g., stainless steel) orpolymers, that provide the desired flexibility.

Referring to FIGS. 34 and 35, the handle portion 308 comprises a housing346 that houses a first gear 348 and a second gear 350. The first gear348 has a shaft that extends through the housing and is connected to thecontrol knob 320 located on the outside of the housing. The second gear350 is disposed on and fixedly secured to the torque shaft 312. Thus,manual rotation of the control knob 320 causes rotation of the firstgear 348, which in turn rotates the second gear 350. The second gear 350rotates the torque shaft 312 and the screw mechanism 314 relative to themain catheter shaft 304, the valve-retaining mechanism 306, and thevalve 10. Rotation of the torque shaft 312 and the screw mechanism 314in turn causes linear movement of the sheath 322 relative to the valve.

In use, the valve 10 is loaded into the sheath 322 in a radiallycompressed state (as depicted in FIG. 30), which can be accomplished,for example, by using the loading cone 124 described above. The deliveryapparatus 300 is then inserted into the patient's vasculature andadvanced to a position at or adjacent the implantation site. The valve10 can then be deployed from the sheath by rotating the knob 320 on thehandle portion, which in turn causes the torque shaft 312 and the screwmechanism 316 to retract within the main shaft 304, causing the sheath322 to move in the proximal direction (arrow 352 in FIG. 31) to exposethe valve, as depicted in FIG. 31. Rotation of the knob 320 enables acontrolled and precise retraction of the sheath 322 during valvedeployment. Advantageously, the sheath is retracted while the positionof the valve can be held constant relative to the annulus at theimplantation site during the unsheathing process. Rotation of the knobin the opposite direction causes the sheath to move in the distaldirection to again cover the valve. Thus, after the valve has been atleast partially advanced from the sheath, it is possible to reverserotation of the knob to bring the valve back into the sheath in acompressed state if it becomes necessary to reposition the deliveryapparatus within the body or to completely withdraw the deliveryapparatus and the valve from the body.

After the valve 10 is advanced from the delivery sheath and expands toits functional size (as shown in FIG. 36), the valve remains connectedto the delivery apparatus via the retaining mechanism 306. Consequently,after the valve is advanced from the delivery sheath, the surgeon canreposition the valve relative to the desired implantation position inthe native valve such as by moving the delivery apparatus in theproximal and distal directions or side to side, or rotating the deliveryapparatus, which causes corresponding movement of the valve. Theretaining mechanism 306 desirably provides a connection between thevalve and the delivery apparatus that is secure and rigid enough toretain the position of the valve relative to the delivery apparatusagainst the flow of the blood as the position of the valve is adjustedrelative to the desired implantation position in the native valve. Oncethe surgeon positions the valve at the desired implantation position inthe native valve, the surgeon can release the connection between thevalve and the delivery apparatus by pulling the proximal end 354 of thenose catheter shaft 326 in the proximal direction (as indicated by arrow356 in FIG. 34) relative to the main catheter shaft 304, which iseffective to retract the inner fork 332 to withdraw its prongs 342 fromthe openings 32 in the retaining arms 30 of the valve (FIG. 37).Retraction of the main catheter shaft 304 retracts the outer fork 330 tocompletely disconnect the valve from the retaining mechanism 306 (asshown in FIG. 37). Thereafter, the retaining mechanism can be retracedback into the sheath 322, the delivery apparatus can be withdrawn fromthe body, leaving the valve implanted within the native valve (such asshown in FIGS. 5A and 5B).

If the surgeon decides to abort the procedure after the valve 10 isfully deployed from the sheath but still connected to the retainingmechanism 306, it may not be possible to retrieve the expanded valveback into the sheath. To such ends, FIGS. 38A-38C show an embodiment ofa valve-retrieving device 400 that can be used with the deliveryapparatus 300 to assist in retrieving the expanded valve 10 back intothe sheath 322. The valve-retrieving device 400 in the illustratedembodiment comprises an elongated, generally cylindrical body that isconfigured to be inserted into the patient's vasculature and advancedover the main catheter shaft 304. The distal end portion of the bodycomprises a plurality of elongated, flexible flap portions 402 that arenormally retained in a compressed state, generally in the form of acylinder (as shown in FIG. 38A) and can flex radially outward from eachother to form a generally cone-shaped receptacle large enough to receivethe proximal end of the expanded valve 10 (FIGS. 38B and 38C). The flapportions 402 desirably are prevented from expanding beyond the expandedstate shown in FIGS. 38B and 38C. In addition, the flap portions 402desirably are dimensioned to overlap each other in the circumferentialdirection so that when the flap portions expand, they form a cone havingcontinuous outer surface without any gaps between the flap portions. Toeffect expansion of the flap portions 402, each flap portion can beconnected to a respective pull wire that extends along the length of theretrieving device 400 to a proximal end thereof. When tension is appliedto the proximal ends of the pull wires, the flap portions are caused toflex radially outward from each other. In addition, the flap portions402 can be made from a mesh material or perforated material, such asperforated foil to allow blood to flow through the flap portions duringthe retrieving process.

Alternatively, the flap portions 402 can be made from a shape-memorymaterial, such as Nitinol, and are self-expanding. The self-expandingflap portions normally assume the expanded configuration shown in FIGS.38A-38B. The flap portions 402 can be held in the radially compressedstate by an outer sheath 406 (FIG. 38A). When the sheath 406 isretracted relative to the flap portions 402 in the direction of arrow408, the flap portions 402 expand to the expanded configuration shown inFIGS. 38A-38B.

As noted above, the retrieving device 400 can be used to retrieve afully expanded valve and remove it from the patient's body. In use, theretrieving device 400 is inserted into the body over the main cathetershaft 304 and advanced toward the deployed valve 10, as shown in FIG.38A. As shown in FIGS. 38B and 38C, the flap portions 402 are thenexpanded and further advanced in the distal direction to engage thevalve. As the retrieving device advances over the valve, the valve iscaused to compress. When the valve is compressed to a diameter smallenough to permit reinsertion into the sheath 322, the sheath 322 isadvanced in the distal direction (e.g., by rotation of knob 320) untilthe sheath extends over the valve. Once the valve is inside the sheath,the retrieving device can be removed from the patient's body, followedby the delivery apparatus and the valve.

In certain embodiments, a portion of the elongated body of theretrieving device 400 can have internal threads that are adapted toengage the threads of screw members 318 (FIG. 32) so that the retrievingdevice can be moved in the distal and proximal directions by rotation ofthe knob 320 (FIG. 34). In use, the retrieving device is inserted intothe body and advanced over the main catheter shaft 304 until thethreaded portion of the retrieving device engages the screw members 318.The flap portions 402 are then expanded and the retrieving device andthe sheath are advanced over the expanded valve by rotation of the knob320. The distal ends of flap portions 402 extend past the distal end ofthe sheath 322 so that as both are advanced, the proximal end of thevalve first comes in contact with the flap portions and begins tocompress to facilitate insertion of the valve into the sheath.

FIG. 39 illustrates a modification of the delivery apparatus 300. Inthis embodiment, the valve 10 is held in its compressed state afterdeployment from the sheath 322 by a restraining device, such as one ormore releasable bands 370 that encircle the valve. The bands 370 can bereleased by pulling or moving a snare device, which allow the bands toopen and the valve to expand. Alternatively, the bands 370 can be madeof a bio-absorbable or soluble material that dissolves in the body afterthe valve is advanced to the implantation site. Because the valve isheld in its compressed state while it is advanced from the sheath, theproblem of the valve “jumping” from the end of the sheath can be avoidedto allow a more controlled delivery of the valve. If the bands 370 orsimilar restraining devices are used, the delivery apparatus can employa conventional pusher shaft that is operable to push the valve throughthe sheath, and need not include a rotatable torque shaft that isrotated to effect deployment of the valve from the sheath. In otherwords, the bands 370 or similar restraining devices can be used with aconventional delivery apparatus where the operator pushes a shaft topush the valve from the sheath. Furthermore, in some embodiments, thedelivery apparatus need not include a sheath that covers the compressedvalve during delivery due to the fact that the restraining device canretain the valve in its compressed state as it is advanced through thepatient's vasculature to the implantation site.

FIG. 40 illustrates a delivery apparatus 400, according to anotherembodiment. The delivery apparatus 400 includes a first, outermost ormain catheter 402 having an elongated shaft 404, the distal end of whichis coupled to a delivery sheath 406 that sized to extend over and retaina prosthetic valve 10 in a compressed state during valve delivery. Theproximal end of the shaft 404 is connected to a handle assembly 408 ofthe delivery apparatus. The delivery apparatus also includes a secondcatheter 410 (also referred to as a valve catheter) having an elongatedshaft 412 extending through the shaft 404. The delivery apparatus canalso include a third, nose catheter 414 having an elongated shaft 416and a nose piece 418 secured to the distal end portion of the shaft 416.The nose catheter shaft 416 extends through the valve catheter shaft 412and can include a lumen for receiving a guidewire. The shafts 404, 412,and 416 desirably are configured to be moveable axially relative to eachother in the distal and proximal directions.

As best shown in FIG. 46, the nose piece 418 can have a tapered distalend portion for atraumatic tracking of the delivery apparatus throughthe patient's vasculature as well as a tapered proximal end portion thatextends into the sheath 406. After the valve is deployed, the taperedproximal end portion of the nose piece allows the nose piece to be moreeasily inserted back into the sheath 406 for withdrawing the deliveryapparatus from the body. The sheath 406 can include a radiopaque tipportion 490 to assist the operator in retracting the nose piece backinto the sheath.

As best shown in FIG. 48, the valve catheter shaft 412 can have one ormore lumens 492 for introducing a contrast media, such as a radiographiccontrast liquid, into the sheath 406 within the space surrounding thevalve. The sheath 406 can have one or more apertures 494 (FIGS. 46 and48) for injecting the contrast media into the patient's vasculature. Thehandle assembly 408 can have a separate an inlet port in fluidcommunication with the lumens 492 for introducing the contrast mediainto the lumens. The contrast media can be injected into the patient'svasculature adjacent the native valve prior to deploying the prostheticvalve to assist in identifying the desired location for implanting theprosthetic valve. For example, when replacing the aortic valve, thecontrast media can be injected into the aorta immediately adjacent thebase of the native leaflets. This provides visual feedback to theoperator to help identify the desired location for deploying theprosthetic valve. After the prosthetic valve is implanted, additionalcontrast media can be injected immediately adjacent the leaflets of theprosthetic valve to provide visual feedback of the operation of theprosthetic valve.

In particular embodiments, the inner diameter of the sheath 406 is about0.265 inch or less and the outer diameter of the sheath is about 0.28inch or less.

Referring to FIG. 41, the handle assembly in the illustratedconfiguration includes a housing 420 that houses the proximal endportions of shafts 404, 412, and 416 and a screw shaft 422. The screwshaft 422 is mounted for longitudinal movement inside the housing 420 onelongated support rods 424. The distal ends of the support rods 424 canbe supported by a distal bracket 426 and the proximal ends of thesupport rods can be supported by a proximal bracket 428. The proximalend of the main shaft 404 can be secured to a stub shaft 430, which inturn can be secured, such as by bonding, to the inside of the screwshaft 422. The screw shaft 422 is operatively connected to an actuator,or control knob, 432, which is operable to control longitudinal movementof the screw shaft 422 and the main shaft 404 upon rotation of the knob,as further described below. The handle assembly 408 can further includea connector 470 mounted at its proximal end. The connector 470 has afirst passageway 472 that is in fluid communication with the lumen ofthe nose catheter shaft 416 for insertion of a guide wire through theshaft 416. The connector 470 can have a second passageway 474 throughwhich the proximal end portion of a release wire 506 extends (describedbelow).

As best shown in FIG. 42, the housing 420 of the handle assembly 408 cancomprise a proximal housing portion 434 and a distal housing portion436. The proximal housing portion 434 can comprise first and secondhousing portions 434 a, 434 b, and the distal housing portion 436 cancomprises first and second housing portions 436 a, 436 b. The screwshaft 422 can include a flush port 462 that extends through a slot 464in the second housing portion 436 b. The flush portion 462 has a lumenthat is in fluid communication with the space between the main shaft 404and the valve catheter shaft 412 for introducing a flush fluid betweenthe shafts.

The control knob 432 can comprise a knob portion 438, a proximalextension 440 that extends into the proximal housing portion 434, and adistal extension 442 that extends into the distal housing portion 436.As best shown in FIG. 41, when the handle assembly is assembled, theknob portion 438 is mounted between the proximal and distal housingportions. The proximal housing portion 434 can be secured to theproximal extension 440 via an annular flange 444 of the proximal housingportion that extends into a corresponding annular groove 446 (FIG. 44)in the proximal extension 440. Similarly, the distal housing portion canbe secured to the distal extension 442 via an annular flange 448 of thedistal housing portion that extends into a corresponding annular groove450 (FIG. 44) of the distal extension 442.

The control knob 432 can include a screw engagement latch 452 mounted onthe distal extension 442. The screw engagement latch 452 is operable toallow a user to selectively engage or disengage the screw shaft 422 forfine or course adjustment, respectively, of the main shaft 404.Explaining further, the screw engagement latch 452 (which can comprisefirst and second latch portions 452 a, 452 b) is mounted within upperand lower slots 454 formed in the distal extension 442 of the controlknob. As best shown in FIG. 45, the latch 452 has upper and lowerinwardly extending flanges 456 that extend through the slots 454 and canengage the external threads of the screw shaft 422. The latch 452 isalso formed with arcuate upper and lower internal surfaces 458 adjacentthe flanges 456. The latch 452 is slidable on the distal extension 442in the lateral direction (as indicated by double headed arrow 460)between an engaged position wherein the flanges 456 extend through slots454 and engage the screw shaft 422 and a disengaged position wherein thecurved surfaces 458 are aligned within the slots 454 and the latchbecomes disengaged from the screw shaft 422. A spring 466 can bedisposed between the distal extension 442 and the latch portion 452 b toretain the latch 452 in the engaged position against the bias of thespring. As best shown in FIG. 43, one end of the spring 466 can beretained in a notch 468 in the side of the distal extension 442 and theother end of the spring can be positioned to bear against the insidesurface of the latch portion 452 b.

When the latch is in the engaged position such that the flanges 456engage the threads of the screw shaft 422, rotation of the control knob432 causes the screw shaft 422 to move longitudinally within the housing420. Since the main shaft 404 is secured to the screw shaft 422,longitudinal movement of the screw shaft causes correspondinglongitudinal movement of the main shaft 404 and the sheath 406 relativeto a valve mounted at the distal end of the valve catheter shaft 412.Rotation of the control knob 432 is effective to move the sheath 406relative to the valve in a precise and controlled manner for controlleddeployment of the valve. When the latch 452 is moved to the disengagedposition such that the curved surfaces 458 are aligned in the slots 454,the latch 452 becomes disengaged from the screw shaft 422 due to thefact that the internal diameter defined by the surfaces 458 is greaterthan the external diameter of the screw shaft 422. In the disengagedposition, the main shaft 404 can be pushed or pulled freely relative tothe control knob 432 for course adjustment of the position of the sheath406. The operator can adjust the position of the sheath 406 either bypushing or pulling on the portion of the main shaft 404 that extendsfrom the housing 420 or by pushing or pulling on the flush port 462(which moves within slot 464).

The valve catheter shaft 412 can comprise a guide catheter that isconfigured to allow a surgeon to guide or control the amount of bendingor flexing of a distal portion of the delivery apparatus to facilitateguiding the delivery apparatus through the patient's vasculature. Forexample, referring to FIGS. 41 and 42, the handle assembly 408 caninclude an adjustment mechanism 476 that is operable to adjust theamount of bending or flexing of the distal end of the deliveryapparatus. The adjustment mechanism 476 can include a rotatableadjustment knob 478 having a distal extension 480 that extends into thehousing 420. The distal extension 480 has a bore formed with internalthreads that engages a slide nut 482, which is supported forlongitudinal movement on a central slide rod 484. Two support rods 486extend between the inner surface of the slide nut 482 and the outersurface of the slide rod 484. Each support rod 486 is supported in anelongated notch in the outer surface of the slide rod 484 and the innersurface of the slide nut 482 so as to restrict rotation of the slide nut482 relative to the adjustment knob 478. By virtue of this arrangement,rotation of the knob 478 (either clockwise or counterclockwise) causesthe slide nut 482 to move longitudinally relative to the slide rod 484in the distal and proximal directions. At least one pull wire (notshown) is secured at its proximal end to the slide nut 482, extendsthrough the handle assembly and the shaft 412 and is secured at itsdistal end at a location adjacent the distal end of the shaft 412. Toincrease the curvature of the distal end portion of the deliveryapparatus, the knob 478 is rotated to cause movement of the slide nut482 in the proximal direction, which in turn pulls the pull wire toincrease the curvature of the delivery apparatus. To decrease thecurvature of the delivery apparatus, the adjustment knob 478 is rotatedin the opposite direction to move the slide nut 482 in the distaldirection, which decreases tension in the pull wire to allow the distalend portion of the delivery apparatus to straighten under its ownresiliency. Further details of an adjustment mechanism for controllingthe bending of a guide catheter are disclosed in U.S. Patent PublicationNos. 2008/0065011 and 2007/0005131, which are incorporated herein byreference.

Referring now to FIGS. 47-49, a prosthetic valve 10 can be secured tothe distal end of the valve catheter shaft 412 via a releasableconnection comprising a plurality of sutures 500 extending from thedistal end of the valve catheter shaft 412. Each suture 500 extendsthrough a hook portion 502 of the valve stent 12 (FIG. 49) and is formedwith a loop 504 through which a release wire 506 extends. The releasewire 506 can extend through a spacer 508 mounted on the nose cathetershaft 416 to maintain the release wire in parallel alignment with thenose catheter shaft. The release wire 506 further extends through thevalve catheter shaft 412, the handle assembly 408, and the connector 470(FIG. 41). As best shown in FIG. 48, the sutures 500 can extend throughapertures in a tip portion 510 of the valve catheter shaft and are tiedoff to each other or otherwise secured to the tip portion 510 to securethe sutures 500 relative to the valve catheter shaft. It should be notedthat the entire valve 10 is not shown; only the valve stent 12 is shownin FIG. 49 for purposes of illustration. The valve 10 can have aconstruction similar to that shown in FIGS. 1-2.

During valve delivery, the valve is mounted in a radially compressedstate within the sheath 406. In order to deploy the valve from thesheath 406, the sheath is retracted relative to the valve, either byrotation of the control knob 432 (when the latch 452 is in the engagedposition) or by pulling the main shaft 404 in the proximal direction(when the latch 452 is in the disengaged position). Retraction of thesheath 406 uncovers the valve, which expands to its functional sizewhile remaining connected to the valve catheter shaft 412 via sutures500, as shown in FIG. 49. Since the valve remains connected to the valvecatheter shaft 406, the position of the expanded valve can be adjustedby moving the handle assembly 408 of the delivery apparatus. Once thevalve is in its desired position for implantation, the valve can bereleased by retracting the release wire 506 to release the suture loops504 from the release wire, thereby releasing the sutures 500 from thehook portions 502 of the valve. The release wire 506 can be retracted bypulling on the proximal end of the release wire that extends from theconnector 470 on the handle (FIG. 41).

FIG. 50 shows an alternative connection technique for forming areleasable connection between the valve and the valve catheter shaft412. This embodiment is similar to the embodiment shown in FIG. 48,except that the sutures 500 are not secured relative to the tip portion510. Instead, the proximal end portions 512 of the sutures are fixedlysecured to a sliding release mechanism (not shown), such as an elongatedshaft or wire that extends through the valve catheter shaft 412. Whilethe valve is connected to the shaft 412 by the sutures 500, the releasemechanism can be moved distally to increase the slack in the sutures 500to permit controlled expansion of the hook portions 502 of the valve.The release mechanism can be operatively connected to a sliding orrotating knob located on the handle assembly that can be operated by theuser to effect sliding movement of the release mechanism. In use, thesheath 406 is retracted relative to the valve. This allows the stent 12to expand, except for the hook portions 502, which are bent inwardly asthey are still connected to the sutures 500. Prior to retracting therelease wire 506, the sliding release mechanism is moved distally toincrease the slack in the sutures 500, allowing controlled radiallyexpansion of the hook portions 502 of the stent. Once the stent is fullyexpanded, the release wire 506 can be retracted to release the hookportions 502 of the stent from the sutures 500.

FIG. 51 shows another embodiment of a connection technique for forming areleasable connection between the valve and the valve catheter shaft412. In this embodiment, a plurality of tethers 514 (one for each hookportion 502 of the stent) extend from the distal end of the valvecatheter shaft 412. The distal end of each tether 514 is secured to arespective attachment element 516, which is connected to a respectivehook portion 502 by a suture 518. Each suture 518 has one end securelyfixed to an attachment element 516, extends through a hook portion 502and an opening 520 in the attachment element 516, and has a loop 521 atits opposite end. For each tether 514 and attachment element 516, arelease wire 522 extends from the distal end of the shaft 412 andthrough the loop 521 of the respective suture 518. The proximal ends ofthe tethers 514 can be secured to a sliding release mechanism that canbe moved distally to increase the slack in the tethers 514 to permitcontrolled radially expansion of the hook portions 502 of the stentafter the sheath 406 is retracted to deploy the valve from the sheath.Once the stent is fully expanded, each release wire 522 can be retractedto release the respective suture 518, which is then pulled back throughthe opening 520 to release the hook portion 502. Each release wire 522can be retracted independently, for example by pulling on the proximalend of each release wire that extends from the handle assembly 408.Alternatively, each release wire 522 can be connected to a common knobon the handle assembly that can be retracted or rotated tosimultaneously retract the release wires in unison.

FIGS. 52A and 52B illustrate the distal end portion of a deliveryapparatus 600, according to another embodiment. The delivery apparatus600 includes a catheter shaft 602 having a nose piece 604 at its distalend and an annular recessed portion 606 for receiving a self-expandablestented valve 608 (shown schematically in FIGS. 52A and 52B). A flexibleouter sheath, or sleeve, 610 extends over the catheter shaft 602 and thevalve 608 and maintains the valve in its compressed state within therecessed portion 606 for delivery through a patient's vasculature. Thedistal end portion of the sheath 610 that covers the valve is a foldedportion having an outer fold layer 612 and an inner fold layer 614. Theproximal end 616 of the inner fold layer 614 is secured (e.g., using anadhesive) to the outer surface of the catheter shaft 602. In use, theouter fold layer 612 can be pulled in the proximal direction, asindicated by arrows 618, to uncover the valve and allow it to expand, asshown in FIG. 52B. The sleeve 610 desirably exhibits sufficient rigidityto maintain a cylindrical shape against the outward expansion force ofthe valve 608 yet is flexible enough to allow the outer fold layer to bepulled back relative to the inner fold layer. Optionally, a thin fluidlayer 620 can be formed between the outer fold layer 612 and the innerfold layer 614 to lubricate and minimize friction the adjacent surfacesof the fold layers. An advantage of the delivery apparatus 600 is thatthere are no frictional forces generated between the sleeve 610 and thevalve 608 as the sleeve is pulled back, and as such, less force isneeded by a user to release the valve from its compressed, sheathedstate.

The sleeve 610 can be constructed from any of various materials,including various polymers (e.g., nylon or PTFE) or metals (e.g.,Nitinol). The sleeve can comprise one or more layers of material, whichcan be, for example, a braided layer, a mesh layer, a non-perforatedlayer or any combinations thereof. Although not shown in the figures,the sleeve 610 can extend to the handle of the delivery apparatus formanipulation by a user. Alternatively, the sleeve 610 can terminateshort of the handle and can be connected to one or more pull wiresextending between the proximal end of the sleeve and the handle, whichpull wires can be pulled proximally to pull back the outer fold layerfor deploying the valve.

Although the nose piece 604 is shown as part of the catheter shaft 602,this is not a requirement. In alternative embodiments, the deliveryapparatus can include an inner nose catheter shaft that extends throughthe shaft 602 and mounts the nose piece 604, as described in theembodiments above. In addition, any of the various connection mechanismsdisclosed herein for forming a releasable connection between the valveand the delivery apparatus can be incorporated in the embodiment shownin FIGS. 52A and 52B. Moreover, the shaft 602 can be the shaft of aballoon catheter having an inflatable balloon at the distal end of theshaft for mounting a balloon-expandable valve on the balloon (in whichcase, the valve need not be self-expandable).

FIGS. 53A-53E illustrate a delivery apparatus 700 according to anotherembodiment. The delivery apparatus 700 comprises an outer catheter shaft702 and an inner catheter shaft 704 extending through the outer shaft.The distal end portion of the outer shaft 702 comprises a sheath thatextends over a prosthetic, stented valve 706 (shown schematically) andretains it in a compressed state during delivery through the patient'svasculature. The distal end portion of the inner shaft 704 is shaped tocooperate with one or more mating extension arms, or posts, 708 thatextend from the stent of the valve 706 to form a releasable connectionbetween the valve and the delivery apparatus. For example, in theillustrated embodiment each post 708 comprises a straight portionterminating at a circular ring portion and the distal end portion of theshaft 704 has correspondingly shaped recesses 710 that receiverespective posts 708. Each recess 710 can include a radially extendingprojection 712 that is shaped to extend into an opening 714 in arespective post 708. As best shown in FIG. 53B, each recess 710 andprojection 712 can be sized to provide a small gap between the surfacesof the post 708 and the adjacent surfaces within the recess tofacilitate insertion and removal of the post from the recess in theradial direction (i.e., perpendicular to the axis of the shaft 704).

When the valve 706 is loaded into the delivery apparatus 700, asdepicted in FIG. 53A, such that each post 708 of the valve is disposedin a recess 710, the valve is retained against axial movement relativeto the shaft 704 (in the proximal and distal directions) by virtue ofthe shape of the posts and the corresponding recesses. Referring to FIG.53D, as the outer shaft 702 is retracted to deploy the valve 706, thevalve is allowed to expand but is retained against “jumping” from thedistal end of the sheath by the connection formed by the posts and thecorresponding recesses for controlled delivery of the valve. At thisstage the partially deployed valve is still retained by the shaft 704and can be retracted back into the outer sheath 702 by retracting theshaft 704 proximally relative to the outer sheath 702. Referring to FIG.53E, when the outer sheath is retracted in the proximal direction pastthe posts 708, the expansion force of the valve stent causes the poststo expand radially outwardly from the recesses 710, thereby fullyreleasing the valve from the shaft 704.

While three posts 708 and corresponding recesses 710 are shown in theillustrated embodiment, any number of posts and recesses can be used.Furthermore, the posts and recesses can have various other shapes, suchas square, oval, rectangular, triangular, or various combinationsthereof. The posts can be formed from the same material that is used toform the valve stent (e.g., stainless steel or Nitinol). Alternatively,the posts can be loops formed from less rigid material, such as suturematerial. The loops are secured to the valve stent and are sized to bereceived in the recesses 710.

FIGS. 54A-54D illustrate a delivery apparatus 800 that is similar to thedelivery apparatus shown in FIGS. 53A-53E. The delivery apparatus 800includes a handle portion 802 having a rotatable knob 804, an outercatheter shaft 806 extending from the handle portion 802, and an innercatheter shaft 808 extending from the handle portion and through theouter catheter shaft 806. The distal end of the inner catheter shaft 808includes an end piece 810 that is formed with an annular recess 812 anda plurality of axially extending, angularly spaced recesses 814. Therecesses 812, 814 are sized and shaped to receive T-shaped posts 816extending from the stent of a valve (not shown in FIGS. 54A-54D). Eachpost 816 has an axially extending portion 816 a that is received in acorresponding recess 814 and a transverse end portion 816 b that isreceived in the annular recess 812. The outer shaft 806 includes asheath 818 that is sized and shaped to extend over the end piece 812 andthe valve during delivery of the valve.

The outer shaft 806 is operatively connected to the knob 804 to effectlongitudinal movement of the outer shaft 806 and the sheath 818 relativeto the inner shaft 808 upon rotation of the knob 804, such as describedabove in connection with the embodiment shown in FIGS. 40-42. In use,the valve is mounted for delivery by placing the posts 816 of the valvein the recesses 812, 814 and moving the sheath distally to extend overthe valve to maintain the valve in a compressed state. At or near thetarget site for implanting the valve, the knob 804 is rotated to retractthe sheath 818 relative to the valve. As the sheath is retracted todeploy the valve, the valve is allowed to expand but is retained against“jumping” from the distal end of the sheath by the connection formed bythe posts and the corresponding recesses for controlled delivery of thevalve. At this stage the partially deployed valve is still retained bythe end piece 810 and can be retracted back into the sheath by movingthe shaft 806 distally relative to the valve. When the sheath isretracted in the proximal direction past the posts 816, the expansionforce of the valve stent causes the posts to expand radially outwardlyfrom the recesses 812, 814, thereby fully releasing the valve from theend piece 810.

FIGS. 55A-55B show an embodiment of an introducer, indicated at 900,that can be used to introduce a catheter or similar device into thebody, for example, a delivery apparatus for delivering and implanting aprosthetic heart valve. The introducer 900 includes an elongated tube,or shaft, 902 sized for insertion into a body channel (e.g., a bloodvessel). The tube 902 extends from a housing 904. Mounted to theproximal end of the housing is a cap portion 906 having a centralopening 908 for receiving a catheter (not shown in FIGS. 55A-55B). Aseal 910 is captured between the opposing faces of the cap portion andthe housing. The seal can be made from any suitable resilient material,such as silicone rubber, or any of various other suitable elastomers.The seal has a central opening 912 that is aligned with the opening 908of the cap portion and the lumen of the tube 902. The seal 910 is sizedto permit a catheter to be inserted through opening 912 while engagingthe outer surface of the catheter to minimize blood loss duringinsertion of the catheter into the body. The proximal end portion of thetube 902 located within the housing has an externally threaded portion914 that engages corresponding internal threads on the inner surface ofthe housing 904. A proximal extension portion 916 of the threadedportion 914 contacts the seal 910. The threaded portion 914 is fixedlysecured to the tube 902, such as with a suitable adhesive. Inalternative embodiments, the tube and threaded portion can have aunitary or one-piece construction where the threaded portion is formeddirectly on the tube.

The housing 904 is moveable longitudinally relative to the tube 902, asindicated by double-headed arrow 917, to selectively dilate or contractthe opening 912 in the seal 910. The housing 904 in the illustratedembodiment is rotatable relative to the tube 902 to effect longitudinalmovement of the housing relative to the tube. As the housing is movedfrom a proximal position (FIG. 55A) to a distal position (FIG. 55B), theseal 910 is stretched against the extension portion 916, which dilatesthe seal opening 912 from a first diameter D1 to a second, largerdiameter D2. As mentioned above, the introducer 900 can be used toassist in the introduction of a valve-delivery apparatus (e.g., deliveryapparatus 100 described above) into the body. In use, the tube 902 isinserted into a blood vessel (e.g., the femoral artery), which can bedilated beforehand in a conventional manner. The housing 904 is thenmoved distally to dilate the opening in the seal to a diameter largeenough to permit passage of the compressed valve (and any sheathcovering the valve) into the lumen of the tube 902. After the valve (orthe largest portion of the delivery apparatus) has passed through theseal, the housing is rotated in the opposite direction to move thehousing proximally to allow the seal opening 912 to contract back to itspre-dilated size. In this state, the seal engages the outer surface ofthe delivery apparatus to prevent or at least minimize blood loss alongthe outer surface of the delivery apparatus.

FIGS. 56A-56B show an introducer 1000, according to another embodiment.This embodiment shares many similarities with the embodiment of FIGS.55A-55B. Hence, components in FIGS. 56A-56B that are identical tocorresponding components in FIGS. 55A-55B have the same respectivereference numerals and are not described further. The introducer 1000differs from the introducer 900 in that the tube 902 of introducer 1000includes an external portion 1002 that slidably engages an inner surfaceof the housing 904. Hence, rather than rotating the housing 904, thehousing can simply be pushed distally relative to the tube 902 in orderto dilate the seal opening 912, as depicted in FIG. 56B. Removal ofmanual pressure from the housing 904 allows the elasticity of the seal910 to pull the housing back proximally for contracting the sealopening.

FIGS. 57A and 57B show an integrated introducer sheath and loaderassembly, indicated at 1100, that can be used to facilitate insertion ofa delivery apparatus (e.g., a valve delivery apparatus) into a bodyvessel. The introducer sheath is particularly suited for use with adelivery apparatus that is used to implant a prosthetic valve, such asthe embodiments of delivery apparatus described herein. The introducersheath also can be used to introduce other types of delivery apparatusfor placing various types of intraluminal devices (e.g., stents, stentedgrafts, etc.) into many types of vascular and nonvascular body lumens(e.g., veins, arteries, esophagus, ducts of the biliary tree, intestine,urethra, fallopian tube, other endocrine or exocrine ducts, etc.).

A conventional introducer sheath typically requires a tubular loader tobe inserted through the seals in the sheath housing to provide anunobstructed path for a valve mounted on a balloon catheter. The loaderextends from the proximal end of the introducer sheath, therebyincreasing its working length, and decreasing the available workinglength of a delivery apparatus that can be inserted into the body. Theintroducer sheath 1100 includes an integrated loader tube housed in thesheath housing to reduce the working length of the sheath and thereforeincrease the available working length of a delivery apparatus that canbe inserted into the body. Moreover, a conventional introducer sheathincludes a cap and a respective seal that typically is removed from theintroducer sheath and preloaded onto the shaft of the delivery apparatusbefore the prosthetic valve is mounted to the distal end of the shaft,and then reattached to the sheath housing as the valve and deliveryapparatus are inserted into the sheath housing. The procedure is carriedout in this manner in order to prevent damage to the prosthetic valvethat otherwise might occur if the valve, while mounted on the shaft in acrimped state, is pushed through the opening in the seal. In some cases,the seal can become dislodged from its intended position within the cap,which can cause damage to the seal. In such cases, the user may need todisassemble the cap and seal assembly for repair or replacement of theseal.

The illustrated assembly 1100 includes a seal housing 1102 and a tubularsleeve 1104 extending distally from the housing. The seal housing 1102houses one or more sealing valves, such as a cross-slit valve 1106, adisc valve 1108, and a hemostatic valve 1110 as shown in the illustratedembodiment. The valves desirably are fabricated from a resilientbiocompatible material, such as polyisoprene, although similarbiocompatible materials also can be used. The valves 1106, 1108, 1110are further shown and described in U.S. Pat. No. 6,379,372, which isincorporated herein by reference. A spacer 1112 can be interposedbetween the cross-slit valve 1106 and the proximal end of the sealhousing.

Coupled to the proximal end of the seal housing is an end piece 1114adapted to move longitudinally along the length of the seal housing. Inthe illustrated embodiment, the end piece has a tubular body formed withinternal threads 1116 that engage an externally threaded portion 1118 onthe outer surface of the seal housing 1102. Thus, rotation of the endpiece 1114 moves the same inwardly and outwardly relative to the sealhousing. The end piece 1114 has a cap portion 1119 at its proximal endhaving a central opening 1120 and an elongated loader tube 1122 fixedlysecured inside the end piece. The opening 1120 and the loader tube 1122are dimensioned to permit passage of a valve (or other prosthesis)mounted on the delivery apparatus. The end piece 1114 also houses a seal1124 having a central opening 1126 aligned with the opening 1120. Theseal 1124 sealingly engages the outer surface of the delivery apparatuswhen it is inserted into the introducer sheath assembly 1100.

As noted above, the end piece 1114 can be adjusted inwardly andoutwardly relative to the seal housing 1102. Adjusting the end piece1114 from the extended position shown in FIG. 57A to the retractedposition shown in FIG. 57B moves the loader tube 1122 through the seals1106, 1108, 1110 to provide an unobstructed path for the valve to passthrough the introducer sheath. Because the loader tube does not extendbehind the end piece, as in a conventional introducer sheath, the loadertube does not decrease the available working length of the deliveryapparatus that can be inserted into the vasculature. In addition, thecap portion 1119 is slidably mounted for longitudinal movement on theend piece 1114 and has an inner tubular portion 1128 that is positionedto engage and stretch the seal 1124. When the cap portion 1119 is pusheddistally relative to the end piece, the tubular portion 1128 stretchesthe seal 1124 and dilates the seal opening 1126 from a first diameter(FIG. 57A) to a second, larger diameter (FIG. 57B) to provide anunobstructed path for the delivery apparatus and the crimped valve intothe assembly. In contrast to a conventional introducer sheath, the capand its respective seal need not be removed from the sheath andpreloaded onto the delivery apparatus prior to mounting the valve ontothe delivery apparatus. As can be appreciated, the configuration of theillustrated embodiment facilitates introduction of the deliveryapparatus into the sheath and avoids possible seal dislodgement duringthe loading process.

In use, the introducer sheath 1100 in the extended position shown inFIG. 57A can be placed on a previously inserted guide wire (not shown)and advanced thereon until the sleeve 1104 extends into a body vessel adesired distance. The cap portion can then be pushed distally to dilatethe seal 1124 to permit passage of the delivery apparatus through theseal opening 1126 to position the valve in the loader tube 1122.Thereafter the cap portion can be allowed to move back to the proximalposition under the elasticity of the seal (FIG. 57A), thereby allowingthe seal 1124 to form a fluid tight seal around the outer shaft of thedelivery apparatus. Subsequently, the end piece 1114 is rotated to slidethe loader tube 1122 through the valves 1106, 1108, 1110 (FIG. 57B),thus placing the delivery apparatus in communication with the lumen ofthe sleeve 1104 and the body vessel in which the sleeve is inserted.Advantageously, this approach simplifies the loading process and reducesthe number of steps and parts required to load the valve into thesheath.

In an alternative embodiment of the introducer sheath 1100, the sealhousing 1102 can have internal threads that engage external threads onthe end piece 1114. The end piece can be rotated to adjust the positionof the loader tube 1122 as previously described. In addition, the pitchof the threads on the seal housing and the end piece can be varied tovary the amount of rotational movement required to extend the loaderthrough the sealing valves. In another embodiment, the end piece 1114can be slidingly positionable along the length of the seal housing bypushing and pulling the end piece without rotating the same. In anotheralternative embodiment, the cap portion can be rotatable relative to theend piece 1114 to effect longitudinal movement of the cap portion fordilating the seal, such as shown in the embodiment of FIGS. 56A and 56B.

Known introducer sheaths typically employ a sleeve made from polymerictubing having a radial wall thickness of about 0.010 to 0.015 inch. FIG.58A shows another embodiment of an introducer sheath, indicated at 1200,that employs a thin metallic tubular layer that has a much smaller wallthickness compared to known devices. In particular embodiments, the wallthickness of the sheath 1200 is about 0.0005 to about 0.002 inch. Theintroducer sheath 1200 includes a proximally located housing, or hub,1202 and a distally extending sleeve, or cannula, 1204. The housing 1202can house a seal or a series of seals as described in detail above tominimize blood loss. The sleeve 1204 includes a tubular layer 1206 thatis formed from a metal or metal alloy, such as Nitinol or stainlesssteel, and desirably is formed with a series of circumferentiallyextending or helically extending slits or openings to impart a desireddegree of flexibility to the sleeve.

As shown in FIG. 58B, for example, the tubular layer 1206 is formed(e.g., laser cut) with an “I-beam” pattern of alternating circular bands1207 and openings 1208 with axially extending connecting portions 1210connecting adjacent bands 1207. Two adjacent bands 1207 can be connectedby a plurality of angularly spaced connecting portions 1210, such asfour connecting portions 1210 spaced 90 degrees from each other aroundthe axis of the sleeve, as shown in the illustrated embodiment. Thesleeve 1204 exhibits sufficient flexibility to allow the sleeve to flexas it is pushed through a tortuous pathway without kinking or buckling.FIG. 59 shows another pattern of openings that can be laser cut orotherwise formed in the tubular layer 1206. The tubular layer in theembodiment of FIG. 59 has a pattern of alternating bands 1212 andopenings 1214 with connecting portions 1216 connecting adjacent bands1212 and arranged in a helical pattern along the length of the sleeve.In alternative embodiments, the pattern of bands and openings and/or thewidth of the bands and/or openings can vary along the length of thesleeve in order to vary stiffness of the sleeve along its length. Forexample, the width of the bands can decrease from the proximal end tothe distal end of the sleeve to provide greater stiffness near theproximal end and greater flexibility near the distal end of the sleeve.

As shown in FIG. 60, the sleeve can have a thin outer layer 1218extending over the tubular layer 1206 and made of a low frictionmaterial to reduce friction between the sleeve and the vessel wall intowhich the sleeve is inserted. The sleeve can also have a thin innerlayer 1220 covering the inner surface of the tubular layer 1206 and madeof a low friction material to reduce friction between the sleeve and thedelivery apparatus that is inserted into the sleeve. The inner and outerlayers can be made from a suitable polymer, such as PET, PTFE, and/orFEP.

In particular embodiments, the tubular layer 1206 has a radial wallthickness in the range of about 0.0005 inch to about 0.002 inch. Assuch, the sleeve can be provided with an outer diameter that is about1-2 Fr smaller than known devices. The relatively smaller profile of thesleeve 1204 improves ease of use, lowers risk of patient injury viatearing of the arterial walls, and increases the potential use ofminimally invasive procedures (e.g., heart valve replacement) forpatients with highly calcified arteries, tortuous pathways or smallvascular diameters.

In an alternative embodiment, a delivery apparatus can be provided witha power source to effect rotation of the torque shaft in lieu of or inaddition to a knob or similar mechanism that uses manual power to rotatethe torque shaft. For example, the handle portion 308 (FIG. 35) canhouse a small electric motor that is connected to and transfersrotational motion to the gear 348. In this way, the user can effectrotation of the torque shaft 312 (to unsheath the valve 10) by simplyactivating the motor of the handle portion. The motor desirably is atwo-way motor so that the torque shaft can be rotated in bothdirections. Alternatively, the power source can be a hydraulic powersource (e.g., hydraulic pump) or pneumatic (air-operated) power sourcethat is configured to rotate the torque shaft.

In another embodiment, a power source (e.g., an electric, hydraulic, orpneumatic power source) can be operatively connected to a shaft, whichis turn is connected to a valve 10. The power source is configured toreciprocate the shaft longitudinally in the distal direction relative toa valve sheath in a precise and controlled manner in order to advancethe valve from the sheath. Alternatively, the power source can beoperatively connected to sheath in order to reciprocate the sheathlongitudinally in the proximal direction relative to the valve to deploythe valve from the sheath.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrated embodiments are only preferred examples of the invention andshould not be taken as limiting the scope of the invention. Rather, thescope of the invention is defined by the following claims. We thereforeclaim as our invention all that comes within the scope and spirit ofthese claims.

We claim:
 1. A method for delivering a prosthetic valve, the methodcomprising: percutaneously introducing a prosthetic valve mounted withina delivery sheath of a delivery apparatus into a body, the prostheticvalve mounted within the delivery sheath in a radially compressed stateand connected to a valve retaining mechanism at a distal end of thedelivery apparatus; advancing the prosthetic valve through the body to adelivery location; actuating a motor to cause the delivery sheath toretract to expose the prosthetic valve; expanding the prosthetic valveto a radially expanded state at the delivery location, thereby deployingthe prosthetic valve; and removing the delivery apparatus from thepatient; wherein the motor is operatively coupled to a torque shaftwithin the delivery apparatus and the torque shaft is operativelycoupled to the delivery sheath, and wherein actuating the motor rotatesthe torque shaft and thereby causes the delivery sheath to retract. 2.The method of claim 1, wherein percutaneously introducing the prostheticheart valve comprises inserting all of the delivery sheath into a bloodvessel of the body.
 3. The method of claim 1, wherein the torque shaftis configured to rotate in a first direction to cause the deliverysheath to retract, and wherein activating the motor to cause thedelivery sheath to retract includes actuating the motor such that themotor causes the torque shaft to rotate in the first direction to causethe delivery sheath to retract.
 4. The method of claim 3, furthercomprising actuating the motor such that the motor causes the torqueshaft to rotate in a second direction opposite the first direction tocause the delivery sheath to advance over the prosthetic valve; andrepositioning the prosthetic valve proximate the delivery location. 5.The method of claim 1, wherein the torque shaft is a first shaft and thedelivery apparatus further comprises a second shaft through which thetorque shaft extends, wherein a distal end portion of the second shaftis coupled to a proximal end portion of the delivery sheath.
 6. Themethod of claim 1, wherein a distal end portion of the torque shaft isconnected to the valve retaining mechanism.
 7. The method of claim 1,wherein the prosthetic valve is held in the radially compressed statewithin the delivery sheath at a location distal to a distal end of thetorque shaft.
 8. A method for delivering a prosthetic heart valve, themethod comprising: disposing a prosthetic heart valve mounted within adelivery sheath of a delivery apparatus in a patient, wherein theprosthetic heart valve is mounted within the delivery sheath in aradially compressed state and is radially expandable to a radiallyexpanded state, wherein the prosthetic heart valve is connected to avalve retaining mechanism; positioning the prosthetic heart valve at anative heart valve annulus; activating a motor to cause the deliverysheath to retract to expose the prosthetic heart valve; and allowing theprosthetic heart valve to radially self-expand at the native heart valveannulus, thereby delivering the prosthetic heart valve; wherein themotor is operatively coupled to a torque shaft of the delivery apparatusand the torque shaft is operatively coupled to the delivery sheath, andwherein activating the motor to cause the delivery sheath to retractincludes actuating the motor such that the motor causes the torque shaftto rotate and thereby causes the delivery sheath to retract.
 9. Themethod of claim 8, wherein the prosthetic heart valve is mounted on adistal end portion of the delivery apparatus, and further comprisingpercutaneously introducing the prosthetic heart valve mounted on thedistal end portion of the delivery apparatus into a blood vessel of thepatient.
 10. The method of claim 9, wherein percutaneously introducingthe prosthetic heart valve comprises percutaneously introducing theprosthetic heart valve through a femoral artery.
 11. The method of claim9, wherein percutaneously introducing the prosthetic heart valvecomprises introducing the prosthetic heart valve through an introducercomprising an elongate tubular sleeve having a lumen, the sleevecomprising a metallic layer comprising a plurality of bands spaced alonga length of the metallic layer and circumferentially extending openingsinterposed between adjacent bands.
 12. The method of claim 8, whereinthe prosthetic valve is connected to the delivery apparatus by theretaining mechanism, and further comprising releasing the prostheticheart valve from the delivery apparatus and removing the deliveryapparatus from the patient after allowing the prosthetic heart valve toradially self-expand.
 13. The method of claim 12, wherein the retainingmechanism comprises a tether, and wherein releasing the prosthetic heartvalve comprises releasing the tether from the prosthetic heart valve.14. The method of claim 8, wherein the torque shaft is configured torotate in a first direction to cause the delivery sheath to retract, andwherein activating the motor to cause the delivery sheath to retractincludes actuating the motor such that the motor causes the torque shaftto rotate in the first direction to cause the delivery sheath toretract.
 15. The method of claim 14, further comprising actuating themotor such that the motor causes the torque shaft to rotate in a seconddirection opposite the first direction to cause the delivery sheath toadvance over the prosthetic valve; and repositioning the prostheticvalve at the native heart valve annulus.
 16. The method of claim 14,wherein rotating the torque shaft in a first direction to retract thedelivery sheath comprises rotating a threaded portion of the torqueshaft to cause axial motion of the delivery sheath.
 17. The method ofclaim 8, wherein the motor is disposed in a handle portion of thedelivery apparatus, and the handle is disposed at a proximal end of thedelivery apparatus.
 18. A method for delivering a prosthetic valve, themethod comprising: percutaneously introducing into a body a prostheticvalve mounted at a distal end of a delivery apparatus within a deliverysheath of the delivery apparatus, wherein the delivery sheath isoperatively coupled to a torque shaft, and wherein the prosthetic valvemounted within the delivery sheath is in a radially compressed state andthe prosthetic valve is connected to a retaining mechanism; advancingthe prosthetic valve through the body to a delivery location;positioning the prosthetic valve at the delivery location; activating amotor such that the motor causes rotation of the torque shaft in a firstdirection to retract the delivery sheath; expanding the prosthetic valveat the delivery location, thereby deploying the prosthetic valve;releasing the prosthetic heart valve from the delivery apparatus; andremoving the delivery apparatus from the patient.
 19. The method ofclaim 18, wherein releasing the prosthetic valve from the deliveryapparatus comprises releasing the prosthetic valve from the retainingmechanism.
 20. The method of claim 19, wherein the retaining mechanismcomprises a tether, and wherein releasing the prosthetic valve from thedelivery apparatus comprises releasing the tether from the prostheticvalve.